World Trade Center Background Study Report : Interim Final

A United States Environmental Protection Agency
DCr^lAKI o New Jersey, New York,
1^1 iiLZ\31I^'IN
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Table of Contents
EXECUTIVE SUMMARY 1
1.0 INTRODUCTION 6
2.0 BACKGROUND AND PROJECT DESCRIPTION 6
2.1 Background 6
2.2 Purpose/Objective 6
2.3 Project Description 7
2.4 Project Team/Responsibilities 8
2 5 Data Usage 8
3 0 SAMPLING APPROACH/RATIONALE 9
3.1 Selection of Sampling Area Location 9
3.2 Selection of Building Types and Obtaining Access 9
3 3 Selection Criteria for Number of Buildings, Residences and
Common Space Sampled 10
3.4 Selection of Contaminants of Potential Concern 10
4.0 SAMPLING METHODOLOGY 11
4.1 Sampling Procedures 11
4 1 1 Indoor Air Sample Collection 12
4.1.2 Microvacuum Sample Collection 12
4.1.3 Wipe Sample Collection 13
4.1 4 Bulk Dust Sample Collection 13
4 1 5 Quality Control Samples 13
4.2 Sampling Equipment .... 15
4 2.1 Air Sampling Equipment 15
4 2 2 Microvacuum Sampling Equipment 15
4 2 3 Wipe Sampling Equipment ... 16
4.2.4 Bulk Sampling Equipment 16
4.3 Sample Numbering/Identification 16
4.4 Sample Shipment 16
4.5 Data Validation and Reporting 17
4.5.1 Validation 17
4 5 2 Venfication . 17
5.0 SAMPLING PROTOCOL DEVIATIONS 18
6.0 ANALYTICAL RESULTS AND DEVELOPMENT OF BACKGROUND
CONCENTRATIONS 19
6.1 Methods 19
6.2 Results and Development of Background Concentrations 22
6 2 1 Asbestos 22
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6 2 2 Man-Made Vitreous Fibers 24
6.2.3 Lead 25
6 2.4 Dioxin . . 26
6 2.5 Polvcvclic Aromatic Hydrocarbons 26
6.3 Minerals and Total Dust Results - Development of Background
Concentrations 27
6.3 1 Crystalline Silica .27
6.3.1.1 Alpha-quartz 27
6 3.1.2 Cristobalite 28
6.3.1.3 Tridymite . ... 28
6.3.2 Calcite 29
6 3.3 Gvpsum 30
6 3.4 Portlandite 30
6 3.5 Total Dust 31
7.0 HISTORICAL STUDIES ON BACKGROUND CHARACTERIZATION
31
7.1 Background Literature Search Results .... 31
7 1.1 Residential Indoor Airborne Asbestos Measurements .... 31
7.1.2 Settled Asbestos Dust Measurements 32
7.1.3 Airborne Man-Made Vitreous Fibers Measurements . . 32
7.1.4 Man-Made Vitreous Fibers in Settled Dust or Soil .... 32
7.1.5 Lead Levels in the Ambient Air 32
7.1.6 Residential Settled Lead Dust Measurements 33
7.1.7 Dioxins in Soil and Settled Dust .• 33
7.1.8 Polvcvclic Aromatic Hydrocarbons in Sediment and Soil
34
7 2 Comparison of WTC Background Study to Other Studies ... 34
7 2 1 Comparison of Airborne Asbestos Concentrations . 34
7.2.2 Comparison of Asbestos Settled Dust Concentrations .... 35
7 2.3 Comparison of Airborne Man-Made Vitreous Fiber (MMVF1
Concentrations .. . . 35
7 2.4 Comparison of Man-Made Vitreous Fibers in Settled Dust or
Soil 35
7.2.5 Comparison of Lead Concentrations in the Ambient Air . . 36
7.2.6 Comparison of Settled Lead Dust Measurements 36
7 2 7 Comparison of Dioxin Concentration in Settled Dust .... 37
7.2.8 Comparison of Polvcvclic Aromatic Hydrocarbon
Concentration in Settled Dust 38
8 0 DISCUSSION 38
REFERENCES 43
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FIGURES
Figure 1 World Trade Center Background Study and WTC Dust Cleanup
Program Areas
TABLES
Table 4-1 WTC Background Study Sampling and Analytical Procedures
Summary
Table 4-2 WTC Background Study Field Sample Collection Summary
Table 4-3 Quality Control Wipe Spike Sample Results For Lead
Table 6-1 Organic and Inorganic Results Summary for Residential and
Common Spaces
Table 6-2 Organic and Inorganic Results Summary for Residential Spaces
Table 6-3 Organic and Inorganic Results Summary for Common Spaces
Table 6-4 Mineral Compounds and Total Dust Results Summary for
Residential and Common Spaces
Table 6-5 Mineral Compounds and Total Dust Results Summary for
Residential Spaces
Table 6-6 Mineral Compounds and Total Dust Results Summary for
Common Spaces
Table 7-1 Summary of U.S. Residential Building Average Indoor
Airborne Asbestos Concentrations for Asbestos Fibers3 5 mm
Long by Direct Transmission Electron Microscopy
Table 7-2 Summary of Settled Asbestos Surface Dust Loadings
Determined Through Microvacuum Sampling and Indirect
Analysis by Transmission Electron Microscopy
Table 7-3 Household Dust Lead Measurements from Wipe Sampling in
an Old, Urban Community
Table 7-4 Estimated Distribution of Lead Loadings (ug/ft2) In U.S.
Housing
Table 7-5 Background Soil Concentrations of Polycyclic Aromatic
Hydrocarbons (PAHs)
Table 8-1 Background Concentrations Derived From The Analytical
Results
Table 8-2 Comparison of Background Concentrations Denved From The
Analytical Results with Literature or Historical Values
Table 8-3 Comparison of Background Concentrations Denved From The
Analytical Results Using Values of Zero, l/z of the Detection Limit,
or the Detection Limit
IV
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ATTACHMENTS
ATTACHMENT A - World Trade Center Indoor Air Assessment:
Selecting Contaminants of Potential Concern and Setting Health-
Based'Benchmarks.
ATTACHMENT B - Data Validation Standard Operating Procedures List
ATTACHMENT C - EMSL Analysis Standard Operating Procedures List
ATTACHMENT D - Sampling and Analytical Methods List
ATTACHMENT E - Photographs of Sample Collection Activities
ATTACHMENT F - NIST Certificate of Analysis, Standard Reference
Material 2581 and Appendix 14.3: Procedure for the Preparation of
Field Spiked Wipe Samples of the Guidelines for the Evaluation
and Control of Lead-Based Paint Hazards m Housing.
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ACKNOWLEDGMENTS
EPA is grateful for the generous contribution of the residents of Manhattan who
provided access to EPA to sample their dwelling units, and of the building owners
who provided access to the common space areas used in this Study.
This project was designed and implemented by EPA with the support of the
Indoor Air Work Group of EPA's Indoor Air Task Force. The work group
organizations directly involved in the development of the project included the
New York City Department of Environmental Protection; New York City
Department of Health and Mental Hygiene; New York City Mayor's Office of
Environmental Coordination; New York City Office of Emergency Management,
New York State Department of Health, Agency for Toxic Substances and Disease
Registry, Occupation Safety and Health Administration, EPA's Office of Solid
Waste and Emergency Response and EPA Region 2.
EPA acknowledges the assistance of New York City's Housing and Preservation
Department for its assistance in identifying Study locations.
Note:
This interim final report is a working document that will be subject to further
Agency and third- party review. EPA intends to excerpt, and possibly expand,
portions of this report for inclusion in manuscripts that will be submitted to
scientific journals for review and consideration for publishing.
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EXECUTIVE SUMMARY
The United States Environmental Protection Agency (EPA) responded to the
September 11, 2001 attack upon the World Trade Center in conjunction with the
President's declaration of a national disaster The Federal Emergency
Management Agency (FEMA), as the federal coordinating office in the disaster,
issued mission assignments to EPA in the areas of cleaning dust/debris from the
streets of lower Manhattan, sampling the ambient environment (air and dust
samples), providing washing stations for personnel working at the WTC response
and recovery site as well as equipment and dust/debns being removed from the
site, and disposal of hazardous materials found at the WTC site.
Residents of lower Manhattan began to raise their concerns about the safety and
reliability of cleaning methods to remove dust and debris from their residential
units and building facades. Traditional FEMA support programs were available.
Yet due to the unprecedented nature of the disaster and on-going concerns,
residents continued to request additional assistance After evaluating the concerns
related to indoor impacts of dust and debris and fire related particle deposition,
EPA Administrator Christine Todd Whitman formed an Interagency Indoor Air
Task Force. This group included representatives from the following agencies, the
regional and national office of the EPA, FEMA, the New York City Department
of Health and Mental Hygiene (NYCDOHMH), the New York City Department
of Environmental Protection (NYCDEP), the New York State Department of
Environmental Conservation(NYSDEC), the New York State Department of
Health (NYSDOH) the Occupational Safety and Health Agency (OSHA), and the
Agency for Toxic Substances and Disease Registry (ATSDR). The group
recommended various issues that could be addressed. Thus, in May 2001, EPA,
FEMA and NYC announced a voluntary cleanup program for residential units,
that would run in parallel to several other efforts to address the concerns of lower
Manhattan residents regarding the potential risks from exposure to residual WTC
dust and debris These efforts were funded by FEMA through interagency
agreements with EPA and NYC and include:
• identification of the Contaminants of Potential Concern (COPCs)
• a background study of the COPCs in upper Manhattan (Background
Study)
inspection and cleaning of building exteriors in lower Manhattan
• Indoor Air Residential Assistance - WTC Dust Cleanup Program
• cleaning of unoccupied, uncleaned buildings, and
a study of cleaning techniques in an unoccupied building adjacent to the
WTC site that was directly impacted by the WTC collapse (WTC
WORLD TRADE CENTER BACKGROUND STUDY 1
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Residential Confirmation Cleaning Study)
These efforts have been conducted simultaneously to ensure that residents are
provided the opportunity to have any WTC residual material removed from their
units as quickly as possible.
This report presents the results of the WTC Background Study conducted by EPA
Results from this Study cannot account for the variability with indoor
environments in general (i.e., cross contamination from outdoors to indoors, way
of life and level of cleanliness). The measurements are limited to each specific
apartment or common area sampled at that specific time the samples were
collected.
Project Objectives / Overview
The objective of this Background Study was to determine and/or estimate indoor
baseline levels or background concentrations for the presence of specific
contaminants related to building materials and combustion byproducts that may
be released when building materials are burned during a fire. The background
concentrations derived from this Study will be used to supplement the health-
based benchmarks established m the "World Trade Center Indoor Air Assessment1
Selecting Contaminants of Potential Concern and Setting Health-Based
Benchmarks" document and were identified as a potential source of alternate
cleanup values if the health-based benchmarks were not able to be achieved The
selected Contaminants of Potential Concern (COPC) includes asbestos, lead,
dioxins, polycychc aromatic hydrocarbons (PAHs), fibrous glass and minerals
including crystalline silica (i.e., a-quartz, Cristobal ite, tndymite), calcite, gypsum,
and portlandite.
The number of buildings, residences and common spaces samples were
determined by what could practically be achieved to avoid impeding the project.
The geographical area for the Background Study (78th Street and North) was
selected based on preliminary modeling of meteorological data on September 11,
2001 and shortly thereafter. The modeling was performed by EPA's Office of
Research and Development The distance of buildings sampled in the Study with
respect to the WTC site ranges from 8 to 19 kilometers (5 to 12 miles).
Sampling was conducted in fourteen residential buildings not impacted by the
airborne dust plume which emanated from the WTC site. When possible, samples
were collected from two residential units and from one common area, such as the
lobby, hallway, stairwell, or building laundry facility, in each building. In total
EPA sampled twenty-five residential units and nine common areas within the
fourteen buildings. Results of the Background Study are discussed in general
terms and are not specific to the units sampled.
WORLD TRADE CENTER BACKGROUND STUDY 2
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Data Assessment
The analytical data for each sample collected were evaluated for individual
apartments and cumulatively in data sets (e.g., asbestos wipe sample data for
residential dwellings, common spaces and a combined data set for residential and
common spaces) to derive a background concentration that is representative for
Manhattan.
The evaluation for individual apartments compared the reported results for each
sample to the health-based criteria developed in the "World Trade Center Indoor
Air Assessment: Selecting Contaminants of Potential Concern and Setting
Health-Based Benchmarks" report. The analytical data was presented in tabular
format for each apartment with text that explains the reported results. Any
detected concentration that exceeded the health-based benchmarks were discussed
in detail in writing and orally when requested by owner.
Cumulatively, the data were statistically evaluated in this report to provide a
mean, standard deviation, minimum and maximum. For each analyte and sample
media, a concentration representative of background for Manhattan has been
calculated (see table below) These background concentrations will be used to
supplement the health-based benchmarks established in the "World Trade Center
Indoor Air Assessment: Selecting Contaminants of Potential Concern and Setting
Health-Based Benchmarks" report and may be used as an alternative cleanup
value if the health-based benchmark cannot be achieved.
WORLD TRADE CENTER BACKGROUND STUDY 3
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Revised May 14, 2003
Background concentrations that were derived based on the analytical results from the
samples collected in this study. The concentrations listed in the table represent the 95%
upper confidence limit (UCL) on the arithmetic mean.
Compound
Air
Bulk Dust
Settled Dus
Porous
Surface
t
Hard Surface
Asbestos

n/a (<1%)

6,192 s/cm2R
Asbestos - PCM
0.0023 s/ccR

Asbestos - TEM
AHERA
0.00024 s/ccR

Asbestos - TEM
PCMe
0 00024 s/cc^

MMVF
0 00006 s/cc^
n/a (<1%)

52 s/cm2T
Lead
0.03 |ig/m3T
186 mg/kgR
1.98 jig/ft2T
1.78 jig/ft™
Dioxin

0.693 ng/m2T
PAH

n/a
(<290 |ig/m2)
Alpha-quartz
(w/o max. value)
61.9 ng/m3R
(7 8 ng/m3R)
3.66 %R

79.6 jig/ft2R
Calcite
9 3 fig/m*
3.41 %R

132.3 ng/ft2T
Cnstobalite
9.3 /tg/m3T
4 69 %R

103.7 pg/ft2T
Gypsum
9.3
2.33 %R

49 9 fig/fT
Portlandite
9.3 ng/miT
4.69 %R

99 8pg/ft2T
Tndymite
9 3 fig/m3T
4 69 %R

99 8 fig/ft27
Total Dust

14.4 mg/ft2R
n/a - indicates that a upper confidence limit could not be calculated, value in parenthesis
indicates that the value is less than the detection limit
italics - indicates a theoretical UCL due to all data being below the detection limit
T - indicates the total data set was used
R - indicates only the residential data set was used
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Conclusions
In summary, the data collected from this Study, in which 1158 samples were
collected, provided calculated estimates of background concentrations for
compounds that were identified as COPCs related to the World Trade Center
collapse. The estimates were shown to be consistent with other background
studies and historical data, where comparison data were available (see table
below). These estimates also provide a upper-bound point estimate that can be
used as a background concentration for the COPC report.
Comparison of estimated background values from this study to background or histoncal
values reported in the scientific literature for select compounds.
Compound
Estimated Background
UCL Value
Historical/Literature
Value
Asbestos - PCMe
0 00024 s/cc
0.00022 s/cc(l)
MMVF - air
0.00006 s/cc
*0.0001 f/cc(2)
Lead - air
0.03 jig/m3
0.02 ng/m3(3)
Lead - wipe floors
3.91 |ig/ft2
3.45 ng/ft2(4)
Dioxm - wipe
0 693 ng/m2
0.67 ng/m2(5)
Consumer Product Safety Commission Study 1987
(2) ATSDR 2002
'3* Calculated value from EPA historic ambient air lead data
f4) HUD 2001
^ Chnstmann. 1989
In addition, these data may provide a source to help address data gaps in scientific
literature on background concentrations of building-related materials and
combustion byproducts caused by building fires.
WORLD TRADE CENTER BACKGROUND STUDY 5
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1.0
INTRODUCTION
A Background Study of the Contaminants of Potential Concern (COPCs) in upper
Manhattan was conducted in parallel to several other efforts to address the
concerns of lower Manhattan residents regarding the potential nsks from exposure
to residual WTC dust and debris These efforts were funded by FEMA through
agreements with EPA and the City of New York (NYC).
While there are background reference levels for a few indoor air pollutants,
comprehensive reference levels (i.e , normative concentrations) for typical
residences do not exist for several reasons. In contrast to the situation for many
outdoor air pollutants which have been routinely monitored for decades because
of legislative mandates, no such legislation exists for indoor air pollutants.
Indoor monitoring has been generally limited because of its cost, the difficulty of
obtaining access to residences due to privacy issues as well as the noise and
inconvenience of sampling equipment and monitoring instrumentation. The size
of a nationally representative monitoring network for residences could also be
large and therefore require costly and complex studies because of the need to
capture variability due to regional differences in housing construction, differences
in residential types (e.g., apartments vs. single-family detached houses), seasonal
differences in operation of the residence (e.g., heating vs. air conditioning),
differences in human activities (e.g., smoking, cleaning methods...) occupant
demographics and density, age of housing and related housing maintenance
practices (e g., use of lead-based paint). In summary, useful reference levels for
air pollutants or contaminants indoors typically do not exist.
2.0 BACKGROUND AND PROJECT DESCRIPTION
2.1 Background
In June 2002, EPA entered into an agreement with FEMA in order to continue to
assess the impacts of possible contamination from WTC related dust in indoor
residential environments. As part of this assessment, EPA needed to identify
what levels of pollutants existed in mdoor residential environments in New York
City prior to September 11, 2001 To accomplish this, EPA developed and
implemented a plan for sampling and analyzing the dust present in residential
buildings located in upper Manhattan that were not affected by the collapse of the
WTC from which to infer contamination levels in downtown residential building
prior to September 11, 2001.
2.2 Purpose/Objective
The objective of the Background Study was to determine indoor baseline levels or
background concentrations for the presence of specific contaminants related to
materials used during the construction of buildings, materials that are typically
found within occupied buildings and any combustion byproducts caused by fires.
WORLD TRADE CENTER BACKGROUND STUDY 6
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The background concentrations derived from this Study will be used to
supplement the health-based benchmarks established in the "World Trade Center
Indoor Air Assessment Selecting Contaminants of Potential Concern and Setting
Health-Based Benchmarks" document and were identified as a potential source of
alternate cleanup values if the health-based benchmarks were not able to be
achieved.
The selected COPCs include asbestos in air1 by phase contrast microscopy
equivalent (PCMe), phase contrast microscopy (PCM) and transmission electron
microscopy (TEM) Asbestos Hazard Emergency Response Act (AHERA)2,
asbestos in settled dust, lead m air and settled dust, dioxins in settled dust,
polycyclic aromatic hydrocarbons (PAHs) in settled dust, fibrous glass and
minerals including alpha-quartz, cristobalite and tridymite, hereinafter referred to
as crystalline silica, and other mineral dusts including calcite, gypsum, and
portlandite in both air and settled dust. These contaminants are discussed in detail
in the peer review draft report "World Trade Center Indoor Air Assessment.
Selecting Contaminants of Potential Concern and Setting Health-Based
Benchmarks" provided as Attachment A.
Project Description
Sampling was conducted in fourteen residential Manhattan buildings not
impacted by the airborne dust plume that emanated from the WTC site.
When possible, samples were collecled from two residential units and from one
common area, iuch as the lobby, hallway, stairwell, or shared laundry facility in
each building. In total, EPA sampled twenty-five residential units and nine
common areas within the fourteen buildings Results of the Study are discussed
in general terms and are not specific to the units sampled. In accordance with the
agreement for Consent for Access for Environmental Sampling for the WTC
Background Study, the addresses of the buildings and apartments, including the
identity of the volunteers, will remain confidential.
1 The asbestos air samples were collected according to NIOSH 7400 (PCM)
The sample filters were analyzed using a modified AHERA method Although the total
TEM (AHERA) fiber count was recorded, a separate PCMe count was recorded by
modifying the AHERA method to count only fibers greater than 5|im (micrometer) It is
this modified AHERA PCMe fiber count that was the basis of the asbestos test results
and health based benchmarks
2 The EPA regulates asbestos contaminated materials (ACMs) in schools via the
Asbestos Hazard Emergency Response Act (AHERA) of 1986 The AHERA schools rule
requires all public school districts and private schools to inspect all school buildings for
ACMs; to develop plans to manage asbestos in schools; and to carry out the plans in a
timely fashion The rule also provides an opportunity for parents, teachers, and other
school employees to become familiar with and involved in their school's asbestos
management programs
WORLD TRADE CENTER BACKGROUND STUDY 7
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2.4 Project Team/Responsibilities
EPA Region 2 staff provided overall management and oversight of the project,
identified participant buildings, obtained access to participant buildings and
implemented the field sampling portion of the project with the assistance of
EPA's contractor, TRC Solutions Inc. (TRC). All communication regarding site
work activities, work scheduling, difficulties encountered, deviations from the
QAPP/sampling plan, and project progress was addressed by the EPA Project
Officer on a daily basis. TRC provided deliverables and services associated with
the sampling operations for this project.
2.5 Data Usage
The data generated from this Study were used to establish baseline information on
residential contaminant levels found in typical NYC dwellings.
The analytical data collected were evaluated first for individual apartments and
common areas and second, cumulatively, which consisted of combining data sets
for residential dwellings and common areas (i.e., asbestos wipe sample data for
residential dwellings, common areas and a combined data set for residential and
common spaces) to derive background concentrations representative for
Manhattan.
The confidential evaluation prepared for individual apartments compared the
reported results for each sample to the health-based benchmarks developed in the
peer review draft of the "World Trade Center Indoor Air Assessment: Selecting
Contaminants of Potential Concern and Setting Health-Based Benchmarks"
document. The analytical data for each analyte were presented in tabular format
for each apartment with text that explains the reported results Any sampling that
resulted in detections exceeding the health-based benchmarks was discussed in a
detailed letter and orally when requested by the resident or owner.
Cumulatively, the data were statistically evaluated to provide descriptive statistics
for each analyte and sample matrix. For each analyte, a recommended
concentration that is representative of background concentrations under a given
set of assumptions, for upper Manhattan, is discussed in Section 6.0 and presented
in Table 8-1.
Results from this Study cannot account for the variability with indoor
environments in general (e.g., cross contamination from outdoor environments to
indoor environments, way of life, and level of cleanliness). The measurements
are limited to each specific apartment or common area sampled at that specific
time the samples were collected The selection of sample point locations within
each unit were decided in the field, on a case-by-case basis and do not represent
the entire apartment or common area sampled
WORLD TRADE CENTER BACKGROUND STUDY 8
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3.0 SAMPLING APPROACH/RATIONALE
3.1 Selection of Sampling Area Location
The geographical area (Figure 1) for the Background Study (78th Street and
North) was selected based on preliminary modeling of meteorological data on
September 11, 2001 and shortly thereafter. The modeling was performed by
EPA's Office of Research and Development (Huber, 2003). This geographical
area is an area well north of the portion of Manhattan that may have been affected
by the deposition of particulate matter from the collapse of the WTC The
distance of buildings sampled in the Study with respect to the WTC site ranges
from 8 to 19 kilometers (5 to 12 miles).
The modeling produced isopleth plots which present the dilution of the particulate
emissions from the WTC site. These plots indicate that the plume was dispersed
and diluted, with the concentration of particulate matter ranging from 1,000 to
10,000 times less than at the WTC site as one moves away from the WTC site in a
northeast direction. These isopleths are based on how much the plume was
dispersed and diluted by weather conditions and are not based on the amount of
emissions from the WTC site.
3.2 Selection of Building Types and Obtaining Access
EPA and other members of the Indoor Air Working Group selected the building
types designated for this Study. This Study attempted to focus on sampling sites
that are similar to the downtown residential housing stock. This stock included:
post-1920 non-doorman mid-nse apartments, high-rise condominiums, high-rise
co-operatives, and turn-of-the-century tenements. Downtown residential lofts
could not be represented in the Study, since lofts located uptown are designated
for commercial use oniy.
In order to solicit volunteer participants from the targeted building types, a list of
buildings matching the housing stock described above was provided to EPA and
the NYCDOHMH by the New York City Department of Housing Preservation
and Development (NYCHPD).
Initially, the task of obtaining access to buildings that would be included in the
Study was the responsibility of NYCDOHMH. During the month of June, 2002
EPA assumed the responsibility for obtaining building access. EPA staff
exhausted the list provided by the NYCHPD. Due to the lack of willing
participants on this list, the difficulty with obtaining access, and time constraints
under the Inter-Agency Agreements (IAA), EPA initiated cold calling and
essentially door to door solicitation in order to solicit volunteers and gain access
to buildings for participation in the Study. Therefore, not all of the buildings
sampled as part of the Study were obtained from the list provided. Any building
willing to participate in the Study was considered for sampling until fourteen
buildings were obtained This is a deviation from the initial sampling plan
regarding representation of the diverse housing stock mentioned above. The
WORLD TRADE CENTER BACKGROUND STUDY 9
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buildings sampled were constructed roughly between 1892 and 1981.
EPA began the task of obtaining access to building common areas and residential
units on June 14, 2002 and continued through September 23, 2002. As access
agreements were signed and returned from volunteer participants, appointments
were scheduled for sampling of the building. Sample collection activities were
completed on September 25, 2002.
3.3 Selection Criteria for Number of Buildings, Residences and Common Space
Sampled
The number of buildings, residences and common spaces samples were
determined by what could practically be achieved to avoid impeding the project.
There were no formal criteria established for selecting the number of buildings to
be incorporated into the study or the number of residential dwellings and common
spaces to be sampled within each building due to the difficulty in obtaining access
and time constraints for conducting the Study.
The objective of the Study was to collect samples from at least three sites within
each building: two or more residential units and one of the building common
spaces. For the most part this objective was met, however in three instances only
one common space and one apartment were sampled per building and in five
buildings access was obtained to sample two residential units per building.
Access could not be obtained to sample the common spaces of these five
buildings.
3.4 Selection of Contaminants of Potential Concern
Under the auspices of the EPA's Interagency Indoor Air Task Force, a committee
was formed to identify the COPCs and associated health-based benchmarks for
the Indoor Air Residential Assistance - WTC Dust Cleanup Program This
committee drafted the "World Trade Center Indoor Air Assessment: Selecting
Contaminants of Potential Concern and Setting Health-Based Benchmarks" report
that was peer reviewed on October 21-22, 2002. This report is currently being
revised for finalization.
Among other purposes, this report identified the selection of contaminants for
monitoring in the WTC Background Study and provided a measure of cleaning
effectiveness by establishing health-based benchmarks and clean-up goals for
indoor air and settled dust As such, the COPCs identified for inclusion in the
Study reflect those contaminants cited in the peer review draft of the
aforementioned report.
The development of the COPC report began with an assessment of the indoor
environment by reviewing historical information on hazardous substances that
have been associated with building fires and collapses. Many compounds,
including combustion byproducts such as dioxins and PAHs were identified,
along with building materials such as asbestos and fibrous glass. In addition,
WORLD TRADE CENTER BACKGROUND STUDY 10
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WTC ambient air, indoor air, and indoor/outdoor bulk dust monitoring data were
reviewed. Data sources included EPA's ambient air and bulk dust/debris
monitoring program www.epa.gov/wtc, OSHA's air and dust monitoring data and
the NYCDOHMH/ATSDR indoor air pilot program (NYCDOHMH 2002). A
concerted effort also was made by the COPC committee to identify and review
additional sources of WTC related data from other governmental agencies (e g.,
U.S Geological Survey, NYC Board of Education), academic institutions,
environmental organizations, and the private sector
A semi-quantitative screening process was performed on the collected sampling
data, referenced above. Based on frequency-of-detection, concentration and
inherent toxicity, contaminants that exceeded health-based screening levels for the
ambient air were identified. Dioxin and PAHs were added to the COPC list by
this process. In addition, building constituents with carcinogenic (asbestos) or
irritant effects (fibrous glass, crystalline silica) that were consistently found m
bulk and indoor dust samples were identified as COPCs (NYCDOHMH 2002).
Finally, lead was included based on a comparison of sampling data with existing
regulatory standards. Collectively, the resulting group of contaminants (asbestos,
lead, dioxin, PAHs, fibrous glass and crystalline silica) are called "contaminants
of potential concern" or COPCs in this report.
4.0 SAMPLING METHODOLOGY
Once building access was obtained and sampling scheduled, air and settled dust
samples were collected from each of the fourteen buildings and shipped to the
laboratories for analysis. All samples were collected and analyzed in accordance
with the approved Quality Assurance Project Plan (QAPP) for the WTC
Background Study, dated August 2002. The procedures used for sample
collection, analysis, data validation, data management and evaluation are
described in or provided as an attachment to the approved QAPP which will be
furnished upon request.
4.1 Sampling Procedures
Samples were collected from twenty five residential units and 9 common spaces
(i e., seven basement laundry rooms and two hallways). Sampling consisted of:
indoor air samples of airborne fibers and particulate matter; microvacuum samples
of settled dust on carpeting, area rugs, upholstered fabric furniture and/or drapery;
wipe samples of settled dust from ceilings, walls, bare floors, counter tops or table
tops; and bulk dust samples from window air conditioner filters. All samples
were collected from areas routinely used and occupied by residents, such as,
living rooms or bedrooms and in common areas, such as, entrance hallways or
basement laundry rooms.
A summary of the sample collection and analytical procedures used are provided
in T able 4-1 of this report. The following subsections provide brief descriptions
of the sampling procedures to place the subsequent discussion of results in
context.
WORLD TRADE CENTER BACKGROUND STUDY 11
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4.1.1 Indoor Air Sample Collection
Airborne fibers and particulate matter were collected by drawing a known volume
of air through a filter membrane cassette following the procedures specified in
Table 4-1. The equipment used for the collection of air samples is provided in
Section 4.2 of this report.
When available and permitted by the resident or building manager, some of the air
sampling was conducted employing the use of oscillating fans and/or operating
the window air conditioning units. How the air conditioning units were utilized
dunng sampling depended upon the unit's features. For example, some units had
the option to recirculate interior air or use outside air. When this option was
available, the unit was set to recirculate interior room air. Other units did not
have this option. The intended purpose for the use of fans or window air
conditioners was to simulate typical household activity within each unit.
The collection of air samples did not employ the use of aggressive techniques due
to the risk of dust exposure to the residents or persons in each unit dunng the
sampling activities. Aggressive sampling techniques employ the use of electric
leaf blowers with a maximum velocity ranging from 140 miles per hour (mph) to
225 mph, and maximum air volumes ranging from 78 cubic feet per minute (cfm)
to 425 cfm in order to agitate dust into the air. The dust then remains suspended
in air by using fans. The aggressive techniques do not simulate "normal"
household activity or living conditions. However, as the goal of the Study was to
estimate background concentrations under typical conditions, the use of non-
aggressive sampling techniques is more representative of typical household
activity and living conditions.
4.1.2 Microvacuum Sample Collection
Samples of settled dust were collected from porous surfaces using microvacuum
techniques and analyzed for asbestos and lead. Porous surfaces included carpet,
area rugs, upholstered couches, chairs, ottomans and in some cases drapery when
furniture and/or carpet were not available.
The standard test method used for the collection of asbestos microvacuum
samples is referenced in Table 4-1. This method describes the procedures for
collecting non-airborne dust samples. It is stated in sub-section 1.2.1 of the
ASTM Standard D 5755-95 that "The collection efficiency of this technique is
unknown and will vary among substrates Properties influencing collection
efficiency include surface texture, adhesiveness, electrostatic properties and other
factors." Due to the limitation of the microvacuum sample collection method for
asbestos, the intended use of the method was to determine only the presence or
absence of asbestos contaminants.
For the purpose of this Study, lead dust samples were collected using
microvacuum techniques for the determination of lead on a loading basis
(microgram of lead per area sampled). As stated in section 1.3 of the ASTM
Standard E 1973-99, "Due to a number of physical factors inherent in the vacuum
WORLD TRADE CENTER BACKGROUND STUDY 12
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sampling method, analytical results for vacuum dust samples are not likely to
reflect the total dust contained within the sampling area prior to sample collection
This practice generally will have a collection bias towards smaller, less dense
particles." Since the bias of this method is known, microvacuum samples
collected for lead analysis were used for determining background loading levels.
4.1.3 Wipe Sample Collection
Wipe samples of settled dust, from nonporous hard surfaces were collected from
each unit and analyzed for asbestos, lead, dioxms, PAHs, crystalline silica, calcite,
gypsum and total dust. The methods used for the collection and analysis of wipe
samples are summarized in Table 4-1.
Wipe sampling employs the use of a cloth-like material (e g., gauze, Ghost
Wipes™ or baby wipes), wetted or pre-moistened with a solution and is
conducted by wiping an area within a template of known size,
4.1.4 Bulk Dust Sample Collection
During the development of the sampling plan and QAPP, no standard method was
found for the collection of dust and particulate matter trapped in window air-
conditioner filters. EPA's contractor TRC developed a procedure to collect this
material by brushing the dust and particulate matter from the filter using a
disposable brush. The dust was collected into a foil-lined stainless steel bowl. If
sufficient material was obtained, the sample was transferred to the appropriate
sample container foT shipment to the laboratory The procedure is noted in Table
4-1 of this report.
In several cases there was not enough material on the window air-conditioner
filter for all of the analyses to be conducted. An order prioritizing the analyses
was established in the event of insufficient material collected. The first container
was sent for the analysis of asbestos and man-made vitreous fibers (MMVF). If
sufficient sample material was collected for the remaining parameters, the second
container was sent for analysis of lead, crystalline silica, calcite and gypsum m
descending priority.
Dust and particulate matter of sufficient amount could not be collected from any
of the apartment air-conditioning unit filters for the analysis of PAHs and dioxins
These parameters require a large quantity of material in order to conduct the
analyses.
4.1.5 Quality Control Samples
Quality control (QC) samples are used to assess the sampling and analytical
processes and to ensure that these processes are being conducted properly. QC
samples were collected during each day of sampling. These samples included
the collection of field spike wipe samples, field blanks and lot blanks. QC
samples were collected for microvacuum, wipe and air samples. QC samples
were not collected with the bulk dust samples due to insufficient material needed
to perform the analyses. Table 4-2 provides a summary of the samples collected
WORLD TRADE CENTER BACKGROUND STUDY 13
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for this project.
As recommended m the Guidelines for the Evaluation and Control of Lead-Based
Paint Hazards in Housing; U S. Department of Housing and Urban Development.
Washington, DC, 1995; Appendix 13.1: Wipe Sampling for Settled Lead-
Contaminated Dust, field spike wipe samples for lead analysis were prepared by
the laboratory. The spike samples were sent to the sampling contractor and
randomly inserted into the sample group for each building, for each day of
sampling. In total, fourteen spike samples were sent indistinguishably to the
laboratory with the actual wipe samples collected for lead analysis. These spike
samples were labeled as ceiling wipe samples on the chain of custody in order to
easily identify the sample results in the database.
Field spike samples were collected for lead analysis in order to assess if the
laboratory digestion procedure used for the wipe material was capable of
achieving recovery within the QC limits of 80 to 120 %. A summary of the
results for the spiked samples and the calculated percent recovery is provided in
Table 4-3. The results of the spike samples indicate that the laboratory was able
to achieve the recovery required for the analysis of lead wipe samples within the
QC limits with the exception of sample numbers 2 and 3 which were barely
outside the QC limits at 79% and 78%, respectively.
Field blanks were collected for microvacuum, wipe and air samples to determine
if the sample media could become contaminated during the sampling event. For
air and microvacuum methods, these samples were collected by opening a
separate air sampling cassette during the sample collection activities to expose it
to the air and then closing the cassette. Wipe field blanks are collected by
removing the wipe from its container or package, shaking the wipe open and re-
folding it as would be done during the actual sampling procedure and placing the
wipe back into the sample container. The field blanks are then labeled, packaged
and shipped with the actual field samples for analysis Results of these samples
indicate that there was no contamination above the reporting limit or health-based
benchmarks that would affect the results or quality of the data.
Lot blanks were collected for microvacuum, wipe and air samples to determine if
the media used to collect the samples were contaminated. The lot blanks are then
labeled, packaged and shipped with the actual field samples for analysis. Results
of these samples indicate that there was no contamination above the reporting
limit or health-based benchmarks that would affect the results or quality of the
data.
WORLD TRADE CENTER BACKGROUND STUDY 14
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4.2 Sampling Equipment
4.2.1 Air Sampling Equipment
ANALYTE
SAMPLE
MEDIA
FLOW
RATE
SAMPLE
PERIOD
SAMPLE
PUMP
Asbestos
(TEM and PCM)
0.8 um (25mm)
MCEF cassette
10 L/min
480 min.
Thomas Medium
Volume
Diaphragm Pump
MMVF
0.8 um (25mm)
MCEF cassette
10 L/min
480 min
Thomas Medium
Volume
Diaphragm Pump
Crystalline
silica, Calcite,
Gypsum,
Portlandite
5 um (37mm) PVC
cassette through an
aluminum cyclone
2.5 L/min
480 min
Gillian GilAir3
personal
sampling pump
Lead
0 8 um (37mm)
MCEF cassette
10 L/min
480 min
Thomas Medium
Volume
Diaphragm Pump
4.2.2 Microvacuum Sampling Equipment
ANALYTE
SAMPLE
MEDIA
FLOW
RATE
SAMPLE
PERIOD
SAMPLE
PUMP
Asbestos (TEM)
0 45 um (25mm)
MCEF cassette
2.0 LPM
2 minutes
Gillian GilAir3
Personal
Sampling Pump
Lead
0.8 um (37mm)
MCEF cassette
2.5 LPM
Minimum of
2 minutes
Gillian GilAir3
Personal
Sampling Pump
WORLD TRADE CENTER BACKGROUND STUDY 15
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4.2.3 Wipe Sampling Equipment
ANALYTE
SAMPLE MEDIA
WETTING
SOLUTION
SAMPLE
CONTAINER
Asbestos, MMVF
9x9 inch, Super
Polx 1200 Class 10
Clean room wipes,
10 to 20 milliliters of a
50 / 50 mixture of 2-
propanol and DI Water
4 oz.
polypropylene
container
Lead, Crystalline
silica, Calcite,
Gypsum, Total
Dust
15 cm x 15 cm,
Ghost Wipes™,
(SKC Inc., No. 225-
24fourteen)
DI Water
50 ml
polyethylene
centrifuge tubes
PAHs, Dioxins
3x3 inch, Cotton
gauze
2 milliliters of acetone
125 ml Amber
glass jars with
PTFE-lined caps
4.2.4 Bulk Sampling Equipment
Sample equipment used for the collection of bulk dust samples from the air-
conditioner unit filters included: disposable brushes, stainless steel bowl,
aluminum foil and 4 oz. polypropylene containers.
4.3 Sample Numbering/Identification
The sample numbering/identification scheme was specific to the addresses,
building identification numbers and apartment numbers sampled. For the purpose
of maintaining confidentiality of the building owners and residents, the sample
numbers are not provided in this report.
4.4 Sample Shipment
All samples were placed in plastic coolers with bagged ice or ice packs and
shipped to the appropriate laboratory for analysis. All sample documentation was
placed and sealed in a plastic bag and affixed to the underside of each cooler lid
The lid was sealed and affixed on at least two sides with custody seals so that any
sign of tampering would be visible.
TRC packaged the samples for shipment/transport to the EPA contracted
laboratory as specified m the table below and on chain of custody forms.
WORLD TRADE CENTER BACKGROUND STUDY 16
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Parameters
Shipment/T ransportation
Method
Laboratory
Dioxins
PAHs
Shipped Overnight Courier
Paradigm Analytical
2627 Northchase Parkway SE
Wilmington, NC 28405
Asbestos
Lead
Total Dust
Crystalline silica
Calcite
Portlandite
Gypsum
MMVF (fibrous glass)
Hand Delivery: Dropped Off
Daily
EMSL would then ship all but
the asbestos samples to their
New Jersey based laboratory
EMSL
307 West 38th Street
New York, NY
EMSL
107 Haddon Ave.
Westmont, NJ
4.5 Data Validation and Reporting
4.5.1 Validation
The validation of all organic and inorganic analytical data were performed by
EPA's Quality Assurance Technical Support (QATS) contractor in accordance
with the Standard Operating Procedures listed in Attachment B.
4.5.2 Verification
Any manual entry of data by the QATS contractor into the database was verified
by the following procedure. This procedure was followed from the inception of
the project for all spreadsheets sent by QATS to EPA for entry into the database.
a. The QATS data analyst entered the validated data into a spreadsheet format.
b. The analyst printed out a hard copy of the spreadsheet and placed it into the
raw data file.
c A second QATS data review analyst then reviewed every entry that was made
into the spreadsheet.
d. The review analyst then returned file to original data entry analyst if errors
were found.
e. Any found errors were corrected and steps b through e were repeated.
f. Documentation of this review and verification is maintained for each data file
by the QATS contractor.
Once the verification of the data were complete, the electronic file was sent to the
EPA Region 2, Data Management Team and loaded into the database. All
WORLD TRADE CENTER BACKGROUND STUDY 17
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analytical results were evaluated and tabulated subsequent to validation and are
presented in Tables 6-1 through 6-6. A detailed discussion of the results and
development of background concentrations is provided in Section 6 0
SAMPLING PROTOCOL DEVIATIONS
The bulk samples collected were to be analyzed in the following order by the
contracted laboratory: asbestos, lead, crystalline silica, calcite, gypsum and
MMVF. Due to the backlog of asbestos samples at the EMSL, New York
laboratory, the samples were shipped to the EMSL, New Jersey laboratory for the
remaining analysis. In performing the analysis for the remaining parameters the
laboratory used all of the material available therefore, the asbestos analysis was
not performed on a majority of the bulk dust samples collected. This was done
without notification to the EPA Project Officer
Bulk dust samples were not collected from the common areas due to the absence
of window air-conditioner units.
The following are deviations from the QAPP for each day of sampling.
August 20, 2002 - Consent to sample was only obtained for one apartment and
the basement laundry room in this building. In the apartment, there was a power
failure for two (2) minutes during sampling. Sampling time was increased by
two (2) minutes to compensate for loss of volume.
August 21,2002 - Air samples could not be collected from the common area as
there were no power outlets in the area. Counter wipes could not be collected due
to lack of horizontal surfaces in the common area. Microvacuum samples could
not be collected from the common area due to absence of porous surfaces.
August 22, 2002 - Microvacuum samples could not be collected from the
common area due to absence of porous surfaces. In one of the apartments, the
pump used for the collection of crystalline silica, calcite and gypsum (SCG)
failed. The sample collection was terminated at that time and the sample data
reflected abbreviated sample duration.
August 29,2002 - There was a power failure of five (5) minutes on pump #3
being utilized for the SCG sample. The sampling time for SCG was increased by
five (5) minutes to compensate for loss of volume. Microvacuum samples could
not be collected from the common area due to absence of a porous surface. Air
samples could not be collected from the common area as there was no power
available in the area.
August 30, 2002 - Microvacuum samples could not be collected from the
common area due to absence of a porous surface. The ceiling wipe sample for
asbestos could not be collected from one apartment due to acoustical texturing.
WORLD TRADE CENTER BACKGROUND STUDY 18
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September 4, 2002 - One apartment and the common area were sampled; access
was denied to the second apartment unit. Microvacuum samples could not be
collected from the common area due to absence of a porous surface. The common
area ceiling wipe sample was collected from the duct work above dryer #3 as the
ceiling had a rough stucco surface which was not suitable for wipe sampling.
September 5, 2002 - The common area was not sampled since the access
agreement was not signed.
September 6, 2002 - Microvacuum samples could not be collected in one
apartment and the common area from carpets/rugs or drapes as none were present
Ceiling samples could not be collected in the common area due to the presence of
a rough surfaced drop ceiling.
September 10, 2002 - A common area was not available for sampling.
September 12, 2002 - Couch/chair microvacuum samples could not be collected
from the apartment. Samples from the common area could not be collected due to
restricted access.
September 24, 2002 - Microvacuum samples could not be collected from the
common area due to absence of a porous surface.
September 25,2002 - High flow air sampling pumps in the common area shut
down for twenty minutes due to power outage in part of the building. Sampling
time was extended twenty minutes to compensate for loss of volume. Air
sampling was terminated 110 minutes early in one unit at the request of the
owner. The owner was called out for the remainder of the day.
6.0 ANALYTICAL RESULTS AND DEVELOPMENT OF BACKGROUND
CONCENTRATIONS
The samples collected during this Study were analyzed to determine the
concentration of each analyte in the matrix in which it was collected. The purpose
of collecting and analyzing the samples was to establish background
concentrations for a select group of compounds that have been identified as
contaminants related to the collapse of the World Trade Center. As stated
previously, these background concentrations will be used to supplement the
health-based benchmarks established in the "World Trade Center Indoor Air
Assessment: Selecting Contaminants of Potential Concern and Setting
Health-Based Benchmarks"document and may be used as an alternative cleanup
value if the health-based benchmark cannot be achieved.
6.1 Methods
Deriving a background concentration for each analyte was completed using the
following guidance; Guidance for Characterizing Background Chemicals in Soil
at Superfund Sites (EPA 540-R-01-003, June 2001), Role of Background in the
WORLD TRADE CENTER BACKGROUND STUDY 19
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CERCLA Cleanup Program (OSWER 9285.6-07P, April 2002), and Calculating
the Upper Confidence Limits for Exposure Point Concentrations at Hazardous
Waste Sites (OSWER 9285.6-10, December 2002).
Evaluating environmental data that are collected to establish background
concentrations of chemicals can be done using a variety of endpoints, such as
reporting ranges, arithmetic or geometric means, or point-estimates based on a
statistical computation. The method that is used to evaluate and interpret the data
is dependent on the application of the background concentration For this study, a
point-estimate that represented an upper-bound of the population mean was the
desired endpoint This resulted in using a statistical approach, specifically
calculating a upper confidence limit (UCL) based on the mean, for estimating an
upper-bound point estimate for each analyte in its associated media.
Several different statistical methods can be used to estimate an UCL of a data set,
depending on the data distribution. Two key steps were completed to estimate the
UCL for these data sets.
1) Determined the distribution of the data (i.e., normal, lognormal, or
neither3) and,
2) Computed the UCL using the appropriate confidence interval4 (e.g.,
95%, 97.5%, 99%) and statistical method for the data distribution
These two steps were performed with the ProUCL statistical software developed
for EPA (Lockheed Martin 2001). Based on EPA guidance (Risk Assessment
Guidance for Superfiind - Part A, 1989) and standard EPA Region 2 procedures,
the samples that were reported as being below the detection limit were assigned a
value equal to one-half the laboratory-reported detection limit for the statistical
calculations5.
3If the distribution of the data is neither normal nor lognormal, it is recommended
to use a non-parametric (i.e., distribution-free) statistic to estimate the UCL
¦"The confidence interval used to estimate the UCL was determined by the
skewness of the data For mild to moderately skewed data sets (e.g., o in the interval of
0.5 to 1) a 95% confidence interval was used, for moderate to highly skewed data sets
(e.g., o in the interval of 1 to 2) a 97.5% confidence interval was used, and for highly to
extremely highly skewed data sets (e g., o in the interval of 2 to 3) a 99% confidence
interval was used.
5A UCL was calculated for any data set that had variability In situations where
all of the samples were below the detection limit, but the detection limit varied, the UCL
that was estimated was identified as a theoretical value because the mean that was
calculated, from which the UCL was derived, was based only upon the detection limit
and it does not include actual detected concentrations Therefore, the UCL associated
with these data sets are theoretical in nature and are reported as such.
WORLD TRADE CENTER BACKGROUND STUDY 20
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The program ProUCL tests the normality/lognormality of each data set using the
Shapiro-Wilk W Test for sample sizes of 50 or smaller, arid using the Lilliefors
Test for sample sizes of 51 to 1000. The data sets for this project included
samples sizes that are less than 50 and greater than 50, therefore both tests were
used depending on the sample size for each analyte. The majority (92%) of the
data sets were neither normally (0.5%) nor lognormally (7%) distributed,
therefore a non-parametric statistic was used to estimate most of the UCLs.
Descriptive statistics, including the minimum, maximum, mean, median, standard
deviation, coefficient of variation, skewness and variance were calculated. In
addition, approximately ten different statistical methods were used to calculate
UCLs for each analyte's data set. The output from these calculations also
reported descriptive statistics for the log-transformed data, which included mean,
standard deviation, coefficient of variation, skewness, median, 80%, 90%, 95%,
and 99% quartiles. The output also included a recommendation regarding which
calculated UCL was most representative of the data set. This UCL is reported in
Tables 6-1 through 6-6.
The UCLs were calculated with the statistical procedures based on the findings of
Singh, Singh, and Engelhardt (1997,1999), as referenced in the ProUCL users
guide (Lockheed Martin, 2001). For normally distributed data sets, the Student's
t-statistic, based on an arithmetic mean, was used to calculate the UCL. For
lognormally distributed data sets, one of five different computational methods was
used, based on the log-transformed mean6, depending on the skewness of the data,
which was indicated by the standard deviation of the log-transformed data, and
the samples size. For data sets that were neither normally nor lognormally
distributed, a UCL based on the non-parametric Chebyshev theorem and
arithmetic mean was used (Lockheed Martin, 2001).
As stated above, these statistical methods were completed for each analyte,
sampling matrix (i e., bulk dust, air, microvacuum, and wipe samples), and space
tested (i.e., resident, common area, and both combined). There were also some
matrices in which multiple surfaces were sampled (e g., counters, floors, and
walls), so additional calculations were conducted for different surfaces. The text
that follows explains the statistical evaluation of the data and the results of the
statistical analyses, as presented in tabular format (Tables 6-1 through 6-6). The
values presented in these tables provide estimates of the background concentration
for each compound and media.
An additional assessment was undertaken to provide a single recommended value
for each analyte for the air, bulk dust, porous materials, and hard surfaces. These
values, which are summarized in Table 8-1, can be used as a representative
background concentration for Manhattan given the statistical limitations of the
data set.
6 The anti-log of the log-transformed mean is equal to the geometric mean
WORLD TRADE CENTER BACKGROUND STUDY 21
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The recommended values were determined using two priorities:
• as first priority, a combined data set, using both the residential and
common areas and all samples from a specific media (e.g., settled dust) to
achieve a larger sample size, was used unless the data from the separate
areas were determined not to be similar7, in which case the second priority
was used;
• the second priority used the data set for the residential areas for all
samples from a specific media, as the residential data sets had the second
largest sample size and this data set would reflect the background
concentration within a residential apartment.
Results and Development of Background Concentrations
The following sections present a summary of the analytical results, the
background values calculated, and a discussion that addresses the strengths and
weaknesses for the asbestos, MMVF, lead, dioxin and PAH data sets, as well as
the corresponding background value that was derived for each analyte, matrix,
type of space, and type of surface. The statistical results and calculated UCLs are
reported in Tables 6-1 through 6-3.
6.2.1 Asbestos8
Bulk Dust - There were three bulk dust samples collected and analyzed for
asbestos. All three samples were collected from the residential spaces. The
results for the three samples were below the detection limit of 1%. Due to the
small sample size and the results all being below the detection limit, the UCL for
asbestos in bulk dust could not be calculated The data suggest that background
asbestos concentrations in bulk dust are less than 1%, however, the confidence in
this statement is limited due to the small sample size.
Air - There were sixty-two air samples collected, forty-eight in residential spaces
and fourteen in common spaces. Each of the samples were analyzed using Phase
Contrast Microscopy (PCM), Transmission Electron Microscopy (TEM) AHERA,
and TEM Phase Contrast Microscopy equivalents (PCMe) methods.
'The frequency of detection, range of detection, mean and calculated UCL for the
residential and common area data sets were qualitatively compared to determine if they
were similar. If any of the parameters were identified as not being similar, the second
priority was used
8For this study, the term structure and fiber are used interchangeably, although
there are mmeralogical nuances and counting rules that make these two terms technically
different In general, the analyses that were completed represent fibers, however for ease
of comparison to the AHERA asbestos standard in a sister study, the term structure was
adopted for all asbestos TEM analyses
WORLD TRADE CENTER BACKGROUND STUDY 22
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PCM - There was a higher percentage of detections in the common space areas
(71%) than in the residential areas (42%) although the minium and maximum
detected concentrations were the same. The UCL for the common area (0.0058
f7cc) is slightly more than twice the value for the residential area (0.0023 f/cc).
This difference may not be an unusual occurrence as common areas, such as
laundry rooms and hallways may contain more fibrous material, especially in
laundry rooms and high traffic areas. Since the common space areas and the
residential areas differ, it is recommended to use the 95% UCL for the residential
spaces of 0 0023 f7cc as the background value.
TEM AHERA - There was a higher percentage of detections in the common space
areas (14%) than in the residential areas (4%) although the minimum and
maximum detected concentrations were the same. In addition, the mean for each
data set were similar. The four samples (two common area and two residential)
that had detectable concentrations of asbestos were at the detection limit of 0 0004
s/cc. Since the frequency of detection was marginally different for the common
space areas and the residential areas, it is recommended to use the 95% UCL for
the residential spaces of 0.00024 s/cc as the background value.
TEM PCMe - There was a higher percentage of detections in the common space
areas (7%) than in the residential areas (4%) although the minimum and
maximum detected concentrations were the same. In addition, the mean for each
data set were almost equal. The three samples (two common area and one
residential) that had detectable concentrations of asbestos were at the detection
limit of 0.0004 s/cc. The UCL for the common areas (0.00029 s/cc) is marginally
higher than the UCL for the residential area (0.00024 s/cc). The combined data
set yields a UCL that is the same value (0.00024 s/cc) as the residential UCL.
Given that the residential areas and the combined data sets provide the same UCL,
it is recommended to use the 95% UCL of 0.00024 s/cc as the background value.
Microvacuum - There were 162 microvacuum samples collected, with 144 from
residential areas and 18 from common spaces. The microvacuum samples were
collected from porous materials, such as carpets, area rugs and couches. These
samples were analyzed for asbestos. The results from these analyses were quite
variable between different surfaces and between the different spaces. Asbestos
was detected more frequently in the common spaces (22%) and at higher
concentrations (mean = 7,145 s/cm2) than in the residential spaces (4%) with a
mean concentration of 2,234 s/cm2. In addition, the carpets in both spaces had
greater mean concentrations than the other porous surfaces (i.e., couches, chairs,
and drapes). As the purpose for collecting microvacuum samples for asbestos was
to determine the presence or absence of asbestos in porous items, a UCL was not
calculated for this data set.
Wipe - There were 146 wipe samples collected, with 104 from residential areas
and 42 from common spaces The wipe samples were collected from hard
surfaces including floors, walls, counters, and ceilings. These samples were
analyzed for asbestos. The results from these analyses were quite variable
WORLD TRADE CENTER BACKGROUND STUDY 23
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between different surfaces and between different spaces. Overall, asbestos was
detected about twice as frequently in the common areas (26%) than in the
residential areas (13%). The results from the common areas had several very high
concentrations reported due to detection limits being unusually high for several
samples. This might artificially increase the background concentrations and for
this reason the common space data sets were not used for determining the
background concentration.
Based on the residential data set, the mean concentration was higher in the ceiling
samples, followed by the floor samples, then the walls, and finally the counters.
The UCLs for these surfaces were within an order of magnitude with the
exception of the UCL for the ceiling, which was one order of magnitude higher.
However, given that the primary goal is to estimate the background concentration
for a residential space, it is recommended to use the entire residential data set,
which includes ceilings, counters, floors, and walls to establish a background
concentration for hard surfaces The 95% UCL for this data set is 6,192 s/cm2 and
would be applicable for all hard surfaces in a residential space.
6.2.2 Man-Made Vitreous Fibers
Bulk Dust - There were twenty-four bulk dust samples collected and analyzed for
MMVF. All of the samples were collected from the residential spaces. The
results for the twenty-four samples were below the detection limit of 1%. As all
of the samples were below the detection limit and the same detection limit was
used throughout the Study, the UCL for MMVF in bulk dust could not be
calculated because there was no standard deviation. The data suggest that
background MMVF concentration in bulk dust is less than 1%, however, the
confidence in this statement is limited due to the small sample size.
Air - There were sixty-two air samples collected, with forty-eight collected from
residential spaces and fourteen collected from common areas. The frequency of
detection for the common spaces (29%) was higher than the residential spaces
(2%), however the range of detections and means were very similar. The UCL for
the combined data set is the same as the UCL for the residential data set. Given
that the UCLs are the same, it is recommended to use the 95% UCL of 0 06 s/L or
0.00006 s/cc.
Wipe - There were 141 wipe samples collected, with ninety-nine collected from
residential spaces and forty-two from common areas. The frequency of detection
was similar between the residential (9%) and the common (11%) areas, as well as
the range of detections and the mean for the wipe data set for each space. Each
space had wipe samples collected from hard surfaces including ceilings, counters,
floors, and walls. The samples collected from the ceiling, counters, and walls in
the common spaces were all below the detection limit and a UCL could not be
calculated for these surfaces. All of the surfaces sampled from the residential
areas had UCLs that were within a factor of three. Given that the residential data
for the different surfaces were similar, as well as the data from the common areas,
it is recommended to use the entire data set, which includes the residential and
WORLD TRADE CENTER BACKGROUND STUDY 24
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common spaces. This data set provides a 95% UCL of 52 s/cm2 as a background
concentration for MMVF on hard surfaces.
6.2.3 Lead
Bulk Dust - There were nine bulk dust samples collected from residential spaces
and analyzed for lead There were no bulk dust samples collected from the
common areas. Lead was detected in all of the bulk samples ranging from 44
mg/kg to 242 mg/kg with a mean concentration of 126 mg/kg. The 95% UCL for
this data set was calculated as 186 mg/kg. This UCL is recommended to be used
as a background concentration for lead in bulk dust.
Air - There were forty-six air samples collected, with thirty-two samples collected
from residential areas and fourteen collected from common areas. Only one
sample, collected from a residential area, had a concentration of lead that was
detectable and the lead concentration was equal to the detection limit. However,
as the detection limit for the common areas and residential area samples varied
slightly, a theoretical background concentration can be calculated for the common
area because the range of detection limits permits a standard deviation to be
calculated. The results indicate that the frequency of detection is similar between
the residential areas (3%) and the common areas (0%), as well as the mean
concentration. The UCL for each space is similar, 0.027 ng/m3 for common areas
and 0.032 jig/m3 for the residential area, therefore it is recommended to use the
entire data set, which includes the common area and residential area, to calculate a
background concentration. The 95% UCL for the entire data set, which should be
considered the calculated background concentration, is 0.03 |ig/m3
Microvacuum - There were 144 microvacuum samples collected, with 114
collected in residential areas and 18 collected in common areas. The
microvacuum samples were collected from porous materials including carpets,
couches, chairs, and drapes. The frequency of detection for all of the
microvacuum samples collected in the residential areas (8%) was similar to the
samples collected in the common areas (6%), as were the ranges, mean, and
calculated UCLs for the data sets for each space and each surface. Given the
similarity between the data sets, both between spaces and between surfaces, it is
recommended to use the entire microvacuum data set for estimating the
background concentration of lead in porous surfaces. This yields a 95% UCL of
1.98 ng/ft2 for the background concentration of lead in porous surfaces.
Wipe - There were 114 wipe samples collected, with 80 collected in residential
areas and 34 collected in common areas. The wipe samples were collected from
hard surfaces including counters, floors and walls. The frequency of detection
between the residential areas (49%) and the common areas (53%) for all of the
wipe samples from each areas are similar, as are the range of detections and
means, with the exception of the maximum detected concentration on the floor in
the common area, which was about five times higher than the residential area.
Although the data sets are very similar for both the spaces and surfaces, the
inclusion of the maximum value for the floor in the common area of 49.2 |ig/ft2 in
WORLD TRADE CENTER BACKGROUND STUDY 25
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Revised May 21, 2003
the entire data for areas skews the data set and results in a 95% UCL of 4 59
Hg/ft2. Alternatively, if only the residential data set is used, the calculated 95%
UCL provides a value of 1.78 ^g/ft2. Either value would be an acceptable
background concentration for hard surfaces, however it is recommended to use the
95% UCL value of 1 78 ^ig/ft2 that was calculated using only the residential data
set because of the marginal difference in the maximum detected concentration in
the common areas and residential areas.
6.2.4 Dioxin
Wipe - There were 114 wipe samples collected, with 80 samples collected from
residential areas and 34 samples collected from common areas. The samples were
collected from hard surfaces including counters, floors, and walls. The samples
were analyzed for dioxin and furan congeners and the results were reported in
2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) equivalents (i.e., TEQs) Any
sample which was below the detection limit for any specific congener group was
assigned a value of/2 of the detection limit before calculating the TEQ, thus for
the statistical analysis the reported TEQ was used without any further
modifications. In addition, the TEQ yalue that was used for estimating the
background concentration was the estimated maximum potential concentration
(EMPC). The TEQ ElylPC value uses data that indicated the detected presence of
a compound above zero but did not meet all of QA/QC reporting level criteria.
The frequency of detection between the residential areas (23%) and the common
areas (20%) were similar, as were the range of detections, means, and UCLs. The
similarity between the data sets for the residential areas and the common areas
permits the use of the entire data set for estimating the background concentration.
The 95% UCL calculated from the entire dioxin data set is 0.693 ng/m2, which
can be used as an estimate of the background dioxin concentration on hard
surfaces.
6.2.5 Polvcvclic Aromatic Hydrocarbons
Wipe - There were 113 wipe samples collected, with 80 samples collected from
residential areas and 33 samples collected from common areas. The samples were
collected from hard surfaces including counters, floors, and walls. The samples
were analyzed for 23 PAH compounds, of which seven of the compounds are used
to calculate a toxicity equivalence factor (TEF). The analytical results indicate
that none of the 23 PAH compounds were detected and the TEF for each sample
would be equivalent to 290 |i.g/m2 The detection limit was the same for each
sample that was analyzed, therefore a UCL cannot be calculated for the residential
or common area data sets due to not having a standard deviation. The data
suggest that the background concentration of PAHs on hard surfaces is less than
the detection limit of 0.25 [xg (i.e., 250 ng/m2) for individual PAHs or 290 jig/m2
for the calculated TEF.
WORLD TRADE CENTER BACKGROUND STUDY 26
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Minerals and Total Dust Results - Development of Background
Concentrations
The following sections present a summary of the analytical results, the calculated
background values and a discussion that addresses the strengths and weaknesses
for the crystalline silica, calcite, gypsum, portlandite and total dust data sets, as
well as the corresponding background value that was derived for each analyte,
matrix, type of space and type of surface The statistical results and calculated
UCLs are reported in Tables 6-4 through 6-6.
6.3.1 Crystalline Silica
6.3.1.1 Alpha-quartz
Bulk Dust - There were nine bulk dust samples collected from residential areas.
These samples were analyzed for alpha-quartz. There were no bulk samples
collected from common areas. Eight of the samples detected alpha-quartz above
the detection limit with a mean value of 2 2%. The 95% UCL for alpha-quartz in
bulk dust is 3.66% and this value can be used as an estimate of the background
concentration.
Air - There were forty-six air samples collected, with thirty-two collected from
residential areas and fourteen collected from common areas. The frequency of
detection for the residential areas (25%) and the common areas (29%) are similar,
although the range of detection and mean concentrations are different. This is
primarily due to one sample value from the residential areas being elevated above
the rest of the samples in the data set. This value was determined to be a valid
result and therefore was kept in the data set. There was some variability between
the residential and common area, primarily due to one sample, however following
the priorities identified earlier it is recommended to use residential data set for
estimating the background concentration due the difference in the maximum
detected concentrations. The 95% UCL for the residential data set is 61.9 fig/m3
which can be used as an estimate of background concentration for alpha-quartz in
air.
Although the value estimated above has been identified as the recommended
background concentration, an additional calculation was conducted without the
elevated value to determine a UCL that is not influenced by the elevated value.
The 95% UCL for the residential data that has the elevated value removed is 7.8
|ig/m3. This value may be more representative of background, however it is
unclear how common the elevated value may be in an urban environment,
therefore the recommended UCL is 61.9 p.g/m3 with the recognition that it may be
much lower (i.e., 7.8 fig/m3).
Wipe - There were 114 wipe samples collected with eighty-one collected from
residential areas and 33 collected from common areas. The wipe samples were
collected from hard surfaces including counters, floors, and walls. The frequency
of detection between the residential areas (38%) and the common areas (61%) for
combined surfaces are not similar and the mean concentration for each type of
WORLD TRADE CENTER BACKGROUND STUDY 27
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surface sampled are riot similar between the residential and common areas. Since
the primary focus of this Study was to determine background concentrations for
residential areas, it is recommended to use the data set for the residential spaces to
estimate the background concentration. The mean concentrations from each of the
surface types in the residential data set are similar, varying by less than a factor of
two, therefore it is recommended to use the entire residential data set, which
includes the results from the counters, floors, and walls. The 95% UCL for this
data set is 79.6 ^g/ft2. This value can be used as an estimate of the background
concentration for alpha-quartz on hard surfaces.
6.3.1.2 Cristobahte
Bulk Dust - There were nine bulk dust samples collected from residential areas.
These samples were analyzed for cristobahte. There were no bulk samples
collected from common areas. None of the samples detected cristobahte above the
detection limit. However, since the detection limit for the samples varied slightly,
a theoretical background concentration can be calculated. The 97.5% UCL for
cristobahte in bulk dust is 4.69% and this value can be used as an estimate of the
background concentration.
Air - There were forty-six air samples collected with thirty-two collected from
residential areas and fourteen collected from common areas. The samples were
analyzed for cnstobalite. Cristobahte was not detected in any sample. However,
since the detection limit for the samples varied slightly, a theoretical background
concentration can be calculated using the entire combined data set from the
residential and common areas. The 95% UCL for the combined data set is 9.3
|ig/m3, which can be used as an estimate of the background concentration of
cnstobalite in air.
Wipe - There were 114 wipe samples collected with eighty samples collected in
residential areas and thirty-four in common areas. The samples were collected
from hard surfaces including counters, floors, and walls. The samples were
analyzed for cnstobalite. The frequency of detection for the residential areas (0%)
and the common areas (3%) were similar, as were the range of detection and mean
concentrations. Based on the similarity of the data sets between spaces and
between surfaces, it is recommended to use the entire data set, combined for
surfaces, to estimate the background concentration. The 95% UCL from this data
set provides a value of 103 7 ng/ft2 as an estimate of the background concentration
of cnstobalite on hard surfaces.
6.3.1.3 Tridymite
Bulk Dust - There were nine bulk dust samples collected from residential areas.
These samples were analyzed for tridymite. There were no bulk samples collected
from common areas None of the samples detected tridymite above the detection
limit. However, since the detection limit for the samples varied slightly, a
theoretical background concentration can be calculated. The 97.5% UCL for
tndymite in bulk dust is 4 69%, and this value can be used as an estimate of the
background concentration.
WORLD TRADE CENTER BACKGROUND STUDY 28
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Air - There were forty-six air samples collected with thirty-two collected from
residential areas and fourteen collected from common areas. The samples were
analyzed for tridymite. Tndymite was not detected in any sample. However, since
the detection limit for the samples varied slightly, a theoretical background
concentration can be calculated using the entire combined data set from the
residential and common areas The 95% UCL for the combined data set is 9.3
Hg/m3, which can be used as an estimate of the background concentration of
tridymite in air.
Wipe - There were 114 wipe samples collected with eighty collected from
residential areas and thirty-four collected from common areas The samples were
collected from hard surfaces including counters, floors, and walls. The samples
were analyzed for tridymite. Tridymite was not detected in any sample, however
since the detection limit for the samples varied slightly, a theoretical background
concentration can be calculated using the entire combined data set for all surfaces
from the residential and common areas. The 95% UCL for the combined data set
is 99.8 ng/ft2, which can be used as an estimate of the background concentration of
tridymite on hard surfaces
6.3.2 Calcite
Bulk Dust - There were rune bulk dust samples collected from residential areas.
These samples were analyzed for calcite. There were no bulk samples collected
from common areas. Only one of the samples detected calcite above the detection
limit The 95% UCL for calcite in bulk dust is 3.41% and this value can be used as
an estimate of the background concentration.
Air - There were forty-six air samples collected with thirty-two collected from
residential areas and fourteen collected from common areas. The samples were
analyzed for calcite Calcite was not detected in any sample However, since the
detection limit for the samples varied slightly, a theoretical background
concentration was calculated using the entire combined data set from the
residential and common areas. The 95% UCL for the combined data set is 9.3
Hg/m3, which can be used as an estimate of the background concentration of calcite
in air
Wipe - There were 114 wipe samples collected with eighty samples collected in
residential areas and thirty-four in common areas. The samples were collected
from hard surfaces including counters, floors, and walls. The samples were
analyzed for calcite. The frequency of detection for the residential areas (3%) and
the common areas (3%) were the same, and the range of detection and mean
concentrations were similar. Based on the similarity of the data sets between
spaces and between surfaces, it is recommended to use the entire data set,
combined for surfaces, to estimate the background concentration. The 95% UCL
from this data set provides a value of 132 3 fig/ft2 as an estimate of the background
concentration of calcite on hard surfaces.
WORLD TRADE CENTER BACKGROUND STUDY 29
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Revised May 14,2003
6.3.3 Gypsum
Bulk Dust - There were nine bulk dust samples collected from residential areas.
These samples were analyzed for gypsum. There were no bulk samples collected
from common areas. Only one of the samples detected gypsum above the
detection limit. The 95% UCL for gypsum m bulk dust is 2.33%, and this value
can be used as an estimate of the background concentration.
Air - There were forty-six air samples collected with thirty-two collected from
residential areas and fourteen collected from common areas The samples were
analyzed for gypsum. Gypsum was not detected in any sample. However, since
the detection limit for the samples varied slightly, a theoretical background
concentration can be calculated using the entire combined data set from the
residential and common areas. The 95% UCL for the combined data set is 9.3
[ig/m3, which can be used as an estimate of the background concentration of
gypsum in air.
Wipe - There were 114 wipe samples collected with eighty collected from
residential areas and thirty-four collected from common areas. The samples were
collected from hard surfaces including counters, floors, and walls. The samples
were analyzed for gypsum. Gypsum was not detected in any sample. However,
since the detection limit for the samples varied slightly, a theoretical background
concentration can be calculated using the entire combined data set for all surfaces
from the residential and common areas. The 95% UCL for the combined data set
is 49.9 fig/ft2, which can be used as an estimate of the background concentration of
gypsum on hard surfaces.
6.3.4 Portlandite
Bulk Dust - There were nine bulk dust samples collected from residential areas.
These samples were analyzed for portlandite. There were no bulk samples
collected from common areas. None of the samples detected portlandite above the
detection limit. However, since the detection limit for the samples varied slightly,
a theoretical background concentration can be calculated The 95% UCL for
portlandite in bulk dust is 4.69% and this value can be used as an estimate of the
background concentration.
Air - There were forty-six air samples collected with thirty-two collected from
residential areas and fourteen collected from common areas. The samples were
analyzed for portlandite. Portlandite was not detected in any sample. However,
since the detection limit for the samples varied slightly, a theoretical background
concentration can be calculated using the entire combined data set from the
residential and common areas. The 95% UCL for the combined data set is 9.3
|jg/m3, which can be used as an estimate of the background concentration of
portlandite in air.
Wipe - There were 114 wipe samples collected with eighty collected from
residential areas and thirty-four collected from common areas. The samples were
collected from hard surfaces including counters, floors, and walls. The samples
WORLD TRADE CENTER BACKGROUND STUDY 30
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were analyzed for portlandite. Portlandite was not detected in any sample.
However, since the detection limit for the samples varied slightly, a theoretical
background concentration can be calculated using the entire combined data set for
all surfaces from the residential and common areas. The 95% UCL for the
combined data set is 99.8 ng/ft2, which can be used as an estimate of the
background concentration of portlandite on hard surfaces.
6.3.5 Total Dust
Wipe - There were nine wipe samples collected from residential areas and
analyzed for total dust. Dust was detected in all nine samples with a mean
concentration of 10.9 mg/ft2. The 95% UCL for this data set was 14.4 mg/ft2,
which can be used as an estimate of the background concentration of total dust
7.0 HISTORICAL STUDIES ON BACKGROUND CHARACTERIZATION
7.1 Background Literature Search Results
The WTC Background Study was conducted to address the following question:
What were the baseline levels for a select group of contaminants in residential
dwellings in lower Manhattan had the Trade Center never collapsed? A complete
set of data were not available that captured the baseline levels of WTC COPCs in
the settled dust and indoor air of residential dwellings in lower Manhattan prior to
9/11/01. However, there are various sources of data that partially address the
specific aim of the WTC Background Study. This section evaluates the findings of
historical studies on background by way of a comparison to the methods and
results of the WTC Background Study.
A search of the literature was conducted for published data on residential indoor
measurements of WTC COPCs The focus was for relevant data, collected m the
past ten to fifteen years, that may be used for comparison with the measurements
from the WTC Background Study. Worth noting are the multiple factors that limit
the representativeness of historical studies to the WTC Background Study. They
include: variations in sampling and analytical methods; characteristics of the
housing stock (e.g., age, type and upkeep) and seasonal variability.
7.1.1 Residential Indoor Airborne Asbestos Measurements
The literature citations on airborne asbestos measurements focused mainly on
occupational environments. Some information is available for schools and other
public buildings. Very few studies described measurements made in residential
settings.
There are a number of analytical techniques (PCM, TEM, direct preparation, and
indirect preparation), as well as different units of measurements reported in the
literature for airborne asbestos concentration. HEI (1991) listed eleven different
measurement units that could be encountered in the literature for asbestos fibers
analyzed by TEM. Another factor to note is how the average or mean value is
determined from a set of measurements Some studies treat all samples with no
asbestos structures/fibers counted as 0 s/cc or 0 f7cc and not as a "less than"
WORLD TRADE CENTER BACKGROUND STUDY 31
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detection limit (Van Orden et al. 1995).
Presented in Table 7-1 is a summary of U.S. residential building average asbestos
concentrations by direct TEM as found in the literature search
7.1.2 Settled Asbestos Dust Measurements
Ewing (2000) reported a geometric mean of 1000 s/cm2 for samples collected in
six buildings without friable asbestos-containing surfacing materials. The 28
microvacuum samples were collected and analyzed as described in the ASTM
Method D 5755-95 or the earlier draft-EPA method (Clark 1989). The sampled
surfaces would be considered non-porous and usually had visible dust on them.
The surface types included polished stone, metal, polished wood, and plastic.
Neither the types of buildings nor their locale were identified. The Study reported a
geometric, rather than arithmetic, mean as a measure of central tendency. Table 7-
2 is extracted from that report.
7.1.3 Airborne Man-Made Vitreous Fibers Measurements
Man-made vitreous fibers (MMVFs) are also known as synthetic vitreous fibers
(SVFs) ATSDR (2001) reported that airborne concentrations of MMVFs in
outdoor and indoor air samples usually are *0 0001 f/cc. Measurements at
workplaces that manufacture MMVF have been reported to be s 0.1 to 1 f7cc.
Airborne concentrations > 1 f/cc have been observed during the installation of
insulation in a home or building, but these high levels would drop to pre-
installation values within 1 or 2 days.
As summarized by ATSDR (2002), a report by Carter et al (1999) used both PCM
and SEM to study air samples from 51 residential and commercial buildings
throughout the United States Only 2 of the 50 samples analyzed by SEM were
found to contain respirable MMVFs The MMVF concentrations were not
included in the ATSDR (2002) summary.
7.1.4 Man-Made Vitreous Fibers in Settled Dust or Soil
According to the ATSDR (2002), no data exist pertaining to the ambient levels of
MMVFs in soil or sediment. The literature search also has not located data on
MMVF loading in residences.
7.1.5 Lead Levels in the Ambient Air
As reviewed by ATSDR (1999), lead levels in the ambient air vary widely but
usually decrease with increasing distance (both vertical and horizontal) from
emission sources. The EPA (1996) has established the National Ambient Air
Quality Standard for lead of 1.5 fag/m\ quarterly average concentration.
Composite urban air measurements of lead for 1991 were reported at 0.08 |ig/m3
(EPA 1996) In 1988, the average lead concentration for 139 urban air-monitonng
sites around the United States was 0.085 (J.g/m3 and remained relatively unchanged,
at 0.04 ng/m3, when estimated between 1994 and 1995 (ATSDR, 1999). Indoor air
lead levels are generally 0.3 to 0.8 times lower than the corresponding outdoor
WORLD TRADE CENTER BACKGROUND STUDY 32
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levels, with an average ratio of 0.5 (ATSDR 1999).
7.1.6 Residential Settled Lead Dust Measurements
Lanpbear et al. (1995) reported lead loading measurements from a study of
residences of 205 children in Rochester, NY House dust samples were collected
using two vacuum methods and a wipe method The geometric mean values from
the microvacuum measurements were 1 (ig/ft2 and 3 jo.g/ft2 for noncarpeted floors
and carpeted floors, respectively. The geometric mean value from their wipe
sample measurements were 16 (ig/ft2 and 11 (ig/ft2 for noncarpeted floors and
carpeted floors, respectively.
Lanphear et al. (1998) reported a geometric mean for floor dust lead loading of
13.5 (ig/ft2 from their pooled analysis of 12 epidemiologic studies
Gallicchio et al. (2002) compared household lead exposure assessment methods in
an old urban community (although the specific locale was not identified). The
median values for dust lead loading were 12 |ig/ft2 and 5 jxg/ft2 for noncarpeted
floors and carpeted floors, respectively. The measurements showed a large
variation in lead load levels. Table 7-3 is extracted from the report's statistics
summary.
The U.S. Department of Housing and Urban Development (HUD 2001) reported
the arithmetic mean for floor dust lead loading stratified by geographic location
and age of housing. Table 7-4 is extracted from the HUD summary statistics.
7.1.7 Dioxins in Soil and Settled Dust
ATSDR (1998) concluded that concentrations of chlorinated dibenzo-/?-dioxins
(CDDs) in soil are typically higher in urban areas than in rural areas. The highest
CDDs in soil concentrations are associated with industrial sites, with CDD levels
ranging from the hundreds to thousands parts per trillion. In general, the
concentration of CDDs m soil near the site of a municipal waste incinerator would
increase in concentration with increasing degree of chlonnation. Heptachlorinated
dibenzo-/?-dioxin (HpCDD) and octa-chlonnated dibenzo-/?-dioxin (OCDD)
congeners are typically found at higher concentrations than the tetrachlorinated
dibenzo-/?-dioxin (TCDD), pentachlorinated dibenzo-/?-dioxin (PeCDD), and
hexachlorinated dibenzo-p-dioxin (HxCDD) congeners in soil and sediments.
Christmann et al. (1989) collected indoor household dust samples and analyzed the
dust samples for CDDs. The dust samples were collected with a vacuum cleaner
from rooms with furniture treated with a wood preservative. The wood
preservative contained CDD-contaminated pentachlorophenol (PCP). Average
mass concentrations of CDDs found in the dust samples were: 191 (ig/kg of
OCDD, 20 |ig/kg of HpCDD, 2.5 jig/kg of HxCDD, 0.9 (ig/kg of PeCDD, and 0.2
Hg/kg of TCDD.
WORLD TRADE CENTER BACKGROUND STUDY 33
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7.1.8 Polvcvclic Aromatic Hydrocarbons in Sediment and Soil
No citation was found during the literature search for surface loading of PAHs in
the indoor residential environment. ATSDR (1995) reported the results of several
studies, published from 1973 through 1987, for background concentrations (ng/kg)
of 15 PAHs in rural, agricultural, and urban soils from the United States and other
countries. The ATSDR summary is reproduced here as Table 7-5.
Comparison of WTC Background Study to Other Studies
Section 7.1 summarized the relevant studies that addressed background
concentrations of COPCs in the residential indoor environment. This section is
focused on the comparison of those studies to the WTC Background Study. As
previously mentioned in Section 7.1, there are numerous factors that limit the
ability to make direct comparisons between studies cited in the open literature that
characterize background levels of the COPCs and the site-specific WTC
Background Study. Thus, a qualitative discussion of study comparability needs to
viewed accordingly Still, where studies were identified that addressed
background concentrations in a manner relevant to the WTC Background Study a
comparison was performed. Where historical studies are described as being
generally concordant with the findings in the WTC Background study, some
disparities in study design, sampling/analytical protocols and results may still
exist.
7.2.1 Comparison of Airborne Asbestos Concentrations
The WTC Background Study obtained airborne asbestos measurements from
residential dwellings and common spaces. Analysis was performed by TEM using
two different counting methods - total asbestos fibers greater than 0.5 |^m (as per
AHERA counting rules), and asbestos fibers greater than 5 ^m (PCMe) - and, by
phase contrast microscopy (PCM). The literature review focused on PCMe
measurements as this metric employs an analytical technique (TEM) that
distinguishes asbestos from other fibrous material and counts only long fibers (i.e.,
> 5 |am) - those most closely associated with adverse health effects (i.e., cancer).
The Consumer Product Safety Commission (CPSC 1987) Study from the literature
review was identified as providing relevant comparisons to the WTC Background
Study. This study reported on airborne asbestos concentration in houses that
contained asbestos containing material (ACM). In 15 houses in Cleveland and 15
houses in Philadelphia the mean asbestos concentration was 0.00023 f/cc and
0.00007 f/cc, respectively A total of 30 samples were taken in Cleveland and 29
in Philadelphia (see Table 7-1) In the WTC Background Study, a total of 62
samples from residences and common spaces (see Table 6-1) were obtained. The
mean asbestos (PCMe) concentration was 0.00022 s/cc. This value is consistent
with the mean value reported from Cleveland and marginally higher than the mean
value reported in Philadelphia.
The primary strength of the above comparison is the common metric (PCMe)
employed to measure airborne asbestos concentration It also focuses on urban
WORLD TRADE CENTER BACKGROUND STUDY 34
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settings similar to New York. However, there are a number of limitations. The
CPSC Study reported on houses with ACM. The known existence of ACM in the
CPSC Study homes would likely serve as a positive bias. Also the particular
housing stock differed, the CPSC Study looked at individual houses whereas the
WTC Background Study focused on apartments. The HE1 (1991) summation of
the CPSC Study did not report the frequency of non-detects or what concentration
was assigned to non-detects
7.2.2 Comparison of Asbestos Settled Dust Concentrations
The WTC Background Study collected measurements of asbestos load (fibers per
unit area) in settled dust by two methods. Microvacuum (ASTM D 5755-95) and
wipe sampling (ASTM D 6480-99). Microvacuum sampling was performed on
porous surfaces (carpets and couches) and resulted in the collection of 162
samples, while 146 wipe samples were collected on hard surfaces (ceilings,
counters, walls and floors). The arithmetic mean for asbestos loading was 2,783
s/cm2 for the microvacuum samples and 37,174 s/cm2 for the wipe samples. The
literature search identified a study by Ewing (2000) that reported a geometnc mean
of 1,000 s/cm2 for samples collected in six buildings without friable asbestos-
containing surfacing materials.
Little in the way of meaningful comparison can be made between the Ewing and
WTC Background Studies. Three significant shortcomings exist. First, unlike the
WTC Background Study, the Ewing Study reports a geometric, rather than
arithmetic, mean. Based on the number of samples (n=28) and maximum value
(210,000 s/cm2), it is evident that the arithmetic mean (calculated by EPA for the
purpose of comparison) was greater (> 7,000 s/cm2) than the geometric mean
(1,000 s/cm2) reported in the Ewing Study. Second, the microvacuum samples in
the Ewing Study were obtained from hard surfaces, whereas the WTC Background
Study used microvacuum sampling only on porous surfaces. Finally, the building
type was not identified in the Ewing Study.
7.2.3 Comparison of Airborne Man-Made Vitreous Fiber (MMVFI
Concentrations
The WTC Background Study reported a mean concentration of 0.000042 s/cc
(95% UCL = 0.00006 s/cc) in a sample size of 62. ATSDR (2002) reported that
airborne concentrations of MMVFs in outdoor and indoor air samples usually are
< 0.0001 f/cc. Accordingly, the airborne concentration of MMVFs in the WTC
Background Study appears consistent with background measurements reported in
the literature although the cited reference is very general and does not provide
sufficient information to make a detailed comparison.
7.2.4 Comparison of Man-Made Vitreous Fibers in Settled Dust or Soil
The WTC background Study reported results of MMVF in bulk dust and wipe
samples. Of the 24 samples collected from bulk dust, all were below the detection
limit of 1%. The following results were reported for 141 wipe samples collected:
frequency of detection (14/141); range (29 - 286 s/cm2) and mean of 38 s/cm2 (95%
UCL = 52 s/cm2). ATSDR (2002) reports that no data exist pertaining to the
WORLD TRADE CENTER BACKGROUND STUDY 35
-------
ambient levels of MMVFs in soil or sediment The literature search also has not
located data on MMVF loading in residences.
7.2.5 Comparison of Lead Concentrations in the Ambient Air
The WTC Background Study reported a mean concentration of 0.027 ^ig/m3. For
the 46 samples collected. No studies on background lead concentration in
residential dwellings were identified in the literature search. ATSDR (1999)
reported that lead levels in the ambient air vary widely but usually decrease with
increasing distance (both vertical and horizontal) from emission sources. The
composite urban air measurement of lead for 1991 was 0.08 |ag/m3 (EPA 1996)
ATSDR (1999) estimated urban airborne levels for the years 1994-1995 to be 0.04
(xg/m3. Indoor air lead levels are generally 0 3-0.8 times lower than the
corresponding outdoor levels, with an average ratio of 0.5 (ATSDR 1999)
From the historical information reported above, a rough estimate of indoor
airborne lead concentration in urban areas can be made by multiplying the
composite ambient air concentration (0 04 (ig/m3) by 0.5 (average value of
indoor/outdoor concentrations) to give a product of 0.02 |ig/m3. This value is
consistent with the mean concentration 0 027 (ig/m3 found in the WTC
Background Study.
7.2.6 Comparison of Settled Lead Dust Measurements
The WTC Background Study recorded lead measurements in settled dust by
concentration (mass per unit mass) and load (mass per unit area). In addition, the
load measurements were obtained by wipes for hard surfaces and microvacuum for
porous surfaces. The following mean measurements were reported for residential
dwellings and common spaces:
Sample Type
Number of Samples
Mean
bulk dust
9
119 mg/kg
microvacuum
162
1.51 ng/ft2
wipe (all samples)
114
1.75 ng/ft2
wipe (all uncarpeted floors)
34
3.91 ng/ft2
wipe (uncarpeted residential floors)
25
1 82 ng/ft2
Unlike the other contaminants included in the WTC Background Study, settled
dust lead levels in residential dwellings have been extensively studied. The study
by Lanphear et al (1998) focused on the relationship between lead-contaminated
house dust and children's blood lead levels. This Study evaluated pooled
epidemiologic data from many different communities, some of them with
significant sources of lead contamination from activities such as mining sand
smelting. Consequently, reported lead levels are likely to be biased high. Another
WORLD TRADE CENTER BACKGROUND STUDY 36
-------
factor that compromises the comparison of results to the WTC Background Study
is that the average lead load (13.5 ng/ft2) on floors is reported as a median rather
than mean value. Lastly, the measurements were performed by multiple sampling
procedures, including wipe sampling and both high/low flow vacuum techniques.
The study by Gallicchio et al. (2002) focused on a comparison of methods (wipe,
questionnaire, and visual inspection) to assess household lead levels. An
advantage is that its targeted community (i.e , "old and urban") is much like New
York City However, the Study selected low socio-economic status (SES)
households (i.e., Medicaid recipients) - which due to less available resources for
building maintenance may result in a positive bias. Also, like the Lanphear Study,
lead loadings (12 |ig/ft2 and 5 ^g/ft2 for non-carpeted floors and carpeted floors,
respectively) were reported as median rather than mean values.
The most appropriate comparison to the WTC background Study can be made with
the Housing and Urban Development (HUD 2001) survey on lead in housing.
Table 7-4 provides the distribution of lead loading by wipe sampling methodology
in U.S. housing for uncarpeted floors. This data is broken down by census region
and building age. In the Northeast, there is a greater than five-fold increase in lead
load in pre-1939 versus post-1939 housing. Excluding the pre-1939 housing
(mean 24.0 |ig/ft2), the weighted mean lead load for 1940 - 1998 housing stock is
3.45 ng/ft2. The results from the HUD evaluation are consistent with the results of
lead load obtained in the WTC Background Study residential units for uncarpeted
floors (i.e., mean = 1.82 ng/ft2 and 95% UCL = 2.96 jag/ft2). This comparison
benefits from both studies reporting results in the same metric (i.e., arithmetic
means) for the same surfaces (uncarpeted floors) by the same methodology (wipe
sampling). A limited disadvantage of the comparison is the gross characterization
of housing by geographic location (e.g., Northeast) in the HUD survey and the
exclusion of pre-1939 housing stock.
7.2.7 Comparison of Dioxin Concentration in Settled Dust
The WTC Background Study reported in a mean dioxin concentration of 0.644
ng/m2 (95% UCL = 0.693 ng/m2) for 80 wipe samples. Results were reported for
dioxin toxicity equivalents (TEQs). The literature search identified no studies that
reported surface loading (mass per unit area) of dioxin in settled dust in residential
dwellings. The study by Chnstmann et al. (1989) reported concentrations (mass
per mass or |ig/kg) of various dioxin congeners (see Section 7.1.7). Converting
these results into dioxin TEQs yields a value of 1 34 ng/kg (or ng/g). Multiplying
by an average dust load of 500 mg/m2 or 0.5 g/m2 results in an estimated dioxin
TEQ load of 0.67 ng/m2 (1 34 ng/g x 0.5 g/m2).
The dioxin TEQ load of 0.67 ng/m2 that was estimated from the Chnstmann Study
is consistent with the mean concentration obtained from the WTC Background
Study. However, the comparison has a number of limitations. The Chnstmann
Study reported dioxin results in units of concentration (mass per mass), thus
necessitating a conversion to the metric (mass per area) used in the WTC
WORLD TRADE CENTER BACKGROUND STUDY 37
-------
Revised May 14,2003
background Study. This required employing an estimate of average dust load in a
residential dwelling, a value that can vary considerably depending on
housekeeping habits. Also, the Christmann Study collected samples from
households that contained furniture treated with a wood preservative. This may
serve to bias the results high. Finally, the Christmann Study employed a vacuum
sampling method whereas the WTC Background Study collected wipe samples
7.2.8 Comparison of Polvcvclic Aromatic Hydrocarbon Concentration in
Settled Dust
All 80 wipe samples collected m the WTC Background Study were reported to be
below the limits of detection (290 ng/m2, benzo[a]pyrene equivalents). No
citations were found in the literature search for surface loading of PAHs in the
indoor residential environment. Consequently, no comparison is possible with the
PAH surface loading results reported in the WTC Background Study.
DISCUSSION
The objective of this Study was to determine indoor baseline levels or background
concentrations for a specific group of compounds that are associated with the
World Trade Center collapse These background concentrations will be used to
supplement the health-based benchmarks established in the "World Trade Center
Indoor Air Assessment Selecting Contaminants of Potential Concern and Setting
Health-Based Benchmarks"document and may be used as an alternative cleanup
value if the health-based benchmark cannot be achieved.
The compounds of interest were asbestos, man-made vitreous fibers, lead, dioxin,
polycyclic aromatic hydrocarbons, and crystalline silica. In addition to these
compounds, data were also collected for calcite, gypsum, portlandite, and total
dust. A combination of air samples, microvacuum samples, wipe samples, and
bulk dust samples were collected to evaluate these compounds in residential
buildings and in common areas of residential buildings. The microvacuum
samples were collected from a variety of porous surfaces, while the wipe samples
were collected from a variety of hard surfaces. The data were evaluated separately
for each type of sample, type of space, and each compound
In addition, the data were evaluated for groups of similar data, such as all
residential lead wipe data. The combined of analyses provided a combination of
192 background concentrations, which represents 95% upper confidence limits on
the arithmetic means Similar subsets of these 192 data points (e.g., by compound
or by media.) were then qualitatively compared to determine a representative
background concentration for each compound in air, bulk dust, porous materials,
and hard materials. The recommended values are presented below in Table 8-1.
The values presented in the table are an upper-bound statistical estimation of the
true mean of the sample population. The upper-bound confidence limit is 95%,
which represents the confidence that the true mean is equal or lower to the value
that is presented in the table
WORLD TRADE CENTER BACKGROUND STUDY 38
-------
Revised May 14, 2003
Table 8-1. Background concentrations that were denved based on the analytical
results from the samples collected in this study. The concentrations listed in the
table represent the 95% upper confidence limit (UCL) on the arithmetic mean.
Compound
Air
Bulk Dust
Settled Dust
Porous
Surface
Hard
Surface
Asbestos

n/a
(<1%)

6,192 s/cm2R
Asbestos - PCM
0.0023 s/ccR

Asbestos - TEM
AHERA
0.00024 s/ccR

Asbestos - TEM
PCMe
0.00024 s/ccm

MMVF
0 00006 s/cc^
n/a
(<1%)

52 s/cm2T
Lead
0.03 pg/m3T
186 mg/kgR
1.98 ^g/ft2T
1.78 ng/ft2R
Dioxin

0.693 ng/m2T
PAH

n/a
(<290 ng/m2)
Alpha-quartz
(w/o max. value)
61.9 ng/m3R
(7.8 |ig/m3R)
3.66 %R

79.6 |xg/ft2R
Calcite
9 3 Mg/m"
3.41 %R

132.3 ng/ft2T
Cristobalite
9.3 /ig/m3T
4.69 %R

103.7 ng/ft2T
Gypsum
9 3 fJg/m3T
2.33 %R

49.9 fig/fF
Portlandite
9.3 /-tg/miT
4.69 %R

99 8 fig/ft1
Tndymite
9.3 fjg/m3r
4.69 %R

99.8 /ig/ft27
Total Dust

Quality Control Samples Collected

Analytical Parameters
Matrix
Sample Media /
Container
Preservative
Holding Time From
Date of Sampling
Samples
Collected
Lot blanks
Field
Blanks
Spike
Blanks
Duplicate
Samples
Total Field
Samples
Asbestos
Microvacuum
0 45 um MCEF 25 mm
20°C (None)
Unlimited
162
14
28
0
*
204
Lead
Microvacuum
0 8 um MCEF 37 mm
20°C (None)
6 months
162
14
28
0
•
204
Asbestos / MMVF
Wipe
9x9 inch Cleanroom
Wipe
20°C (None)
Unlimited
146
14
28
0
14
202
Lead
Wipe
15x15 cm Ghost Wipes
20°C (None)
6 months
114
14
14
14*'
14
170
Dioxins
Wipe
3x3 inch cotton gauze
4°C
7 days to extraction, 40
days to analysis
114
14
14
0
14
156
PAHs
Wipe
3x3 inch cotton gauze
4°C
7 days to extraction, 40
days to analysis
113
14
14
0
14
155
Total Dust
Wipe
15x15 cm Ghost Wipes
20°C (None)
Unlimited
35
14
14
0
3
66
Silica, calate, gypsum
Wipe
15 x 15 cm Ghost Wipes
20°C (None)
28 days
114
14
14
0
14
156
Asbestos / MMVF
Air
0 45 um MCEF 25 mm
20°C (None)
Unlimited
64
13
28
0
32
137
Lead
Air
0 8 um MCEF 37 mm
20°C (None)
6 months
46
14
29
0
14
103
Silica, calate, gypsum
Air
5 um PVC filter 37 mm
20°C (None)
28 days
46
14
28
0
14
102
Asbestos 1 MMVF
Bulk Dust
4 oz. Polypropylene
20°C (None)
Unlimited
24
NC
NC
NC
NC
24
Lead
Bulk Dust
4 oz Polypropylene
20°C (None)
6 months
9
NC
NC
NC
NC
9
Dioxins
Bulk Dust
125 ml Amber Glass
4°C
7 days
NC
NC
NC
NC
NC
0
PAHs
Bulk Dust
125 ml Amber Glass
4°C
7 days to extraction, 40
days to analysis
NC
NC
NC
NC
NC
0
Silica, calate, gypsum
Bulk Dust
4oz Polypropylene
20°C (None)
28 days
9
NC
NC
NC
NC
9
NOTES:
The information provided in Ihis table represents the number of samples and QC samples collected It is not an indication of the
number of sample analytical results reported since several samples were collected for multiple analytes
NC = QC Sample was not collected due to insufficient material.
* Microvacuum samples were collected as co-located triplicate samples therefore duplicate samples were not collected.
** As recommended in the method, spike samples were prepared and submitted with the wipe samples into the sampling
stream for lead analysis only
-------
Table 4-3
Quality Control Wipe Spike Sample Results For Lead
Sample Identification Number
Spike Added (g)
True Value
(ug/wipe) +- 2%
Spike Sample
Results1
(ug/wipe)
Percent
Recovery
QC Limit %
1 Recovery
13-BG-Common Area-Wipe Ceiling 1-L
0.0919
413
361
87%
80-120%
10-BG-Common Area-Wipe Ceiling 1-L
0 1018
457
397
87%
80-120%
11-BG-Common Area-Wipe Ceiling 1-L
0.0997
448
405
90%
80-120%
14-BG-Common Area-Wipe Ceiling 1-L
0.1063
477
414
87%
80-120%
9-BG-Common Area-Wipe Ceiling 1-L
0 1031
463
404
87%
80-120%
4-BG-Wipe Ceiling 1-L
0 0572
257
219
85%
80-120%
2-BG-Common Area-Wipe Ceiling 1 -L
0.0530
238
189
79%
80-120%
8-BG-Wipe Ceiling 1-L
0 0956
429
432
101%
80-120%
3-BG-Wipe Ceiling 1-L
0 0602
270
209
78%
80-120%
5-BG-Wipe Ceiling 1-L
0 0504
226
205
91%
80-120%
1-BG-Common Area-Wipe Ceiling 1-L
0.0540
242
202
83%
80-120%
6-BG-Wipe Ceiling 1-L
0 0708
318
289
91%
80-120%
7-BG-Common Area-Wipe Ceiling 1-L
0 0681
306
294
96%
80-120%
12-BG-Common Area-Wipe Ceifing 1-L
0 0982
441
ND'
-
80-120%
1 Result of the spike sample sent indistinguishably to the lab with field samples
2 It is believed this sample was inadvertently switched at the laboratory with a counter wipe sample
The laboratory could not confirm this result, although the result of the counter wipe was 383 ug/ft2,
where as the ceiling wipe sample was not detected.
-------
Table 6-1. Summary of the analytical results for the organic and inorganic compounds from the background study. The table presents the sample
size, frequency of detection, minimum and maximum detected concentrations, arithmetic mean, the statistic used, and the upper confidence limit
(UCL) for each compound and matrix sampled. The values in this table were calculated using the entire data set for each analyte, which includes
residential and common areas.
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL
Asbestos
Bulk Dust
3
0/3
<0.5%

Air - PCM
64
33/64
0.0005 f/cc
0.007 f/cc
0.0017 fee
95% Chebyshev
(Mean, STD)
0.0027 f7cc

Air - TEM AHERA
62
4/62
0.0002 s/cc
0.0004 s/cc
0.00022 s/cc
95% Chebyshev
(Mean, STD)
0.00025 s/cc

Air - TEM PCMe
62
3/62
0 0002 s/cc
0.0004 s/cc
0.00022 s/cc
95% Chebyshev
(Mean, STD)
0.00024 s/cc

Microvacuum - All
161
21/161
317 s/cm3
72,094 s/cm2
2,783 s/cm2

Microvacuum -
Carpet
69
13/69
317 s/cm2
72,094 s/cm2
3,715 s/cm2

Microvacuum -
Couch
77
6/77
317 s/cm2
24,138 s/cm2
1,818 s/cm2

Wipe - All
146
25/146
592 s/cm2
3,798,910 s/cm2
37,174 s/cm2
97.5%
Chebyshev
(Mean, STD)
207,033 s/cm2
~Minimum detected value includes values that may be Zz of the detection limit
Table 6-1
-------
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Ceiling
32
4/32
592 s/cm2
83,893 s/cm2
3,885 s/cm2
97.5%
Chebyshev
(Mean, STD)
20,109 s/cm2

Wipe - Counter
32
6/32
592 s/cm2
1,183,205 s/cm2
37,910 s/cm2
97.5%
Chebyshev
(Mean, STD)
268,632 s/cm2

Wipe - Floors
34
8/34
592 s/cm2
3,798,910 s/cm2
113,999 s/cm2
97.5%
Chebyshev
(Mean, STD)
811,379 s/cm2

Wipe - Walls
48
7/34
592 s/cm2
149,055 s/cm2
4,460 s/cm2
97.5%
Chebyshev
(Mean, STD)
23,762 s/cm2
MMVF
Bulk Dust
24
0/24
<0.5 %

Air
62
5/62
0.032 s/L
0.216 s/L
0.042 s/L
95% Chebyshev
(Mean, STD)
0.06 s/L

Wipe - All
141
14/141
29 s/cm2
286 s/cm2
38 s/cm2
95% Chebyshev
(Mean, STD)
52 s/cm2

Wipe - Ceiling
31
1/31
29 s/cm2
286 s/cm2
37 s/cm2
95% Chebyshev
(Mean, STD)
73 s/cm2

Wipe - Counter
31
1/31
29 s/cm2
114 s/cm2
31 s/cm2
95% Chebyshev
(Mean, STD)
43 s/cm2
~Minimum detected value includes values that may be V2 of the detection limit
-------
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Floors
33
11/33
29 s/cm2
286 s/cm2
59 s/cm2
95% Chebyshev
(Mean, STD)
103 s/cm2

Wipe - Walls
46
1/46
29 s/cm1
57 s/cm1
29 s/cm1
95% Chebyshev
(Mean, STD)
32 s/cm1
Lead
Bulk Dust
9
9/9
44.5 mg/kg
242 mg/kg
126 mg/kg
95% H-UCL
186 mg/kg

Air
46
1/46
0.026 ng/m3
0.058 n-g/m3
0.027 jig/m3
95% Chebyshev
(Mean, STD)
0.03 ^g/mJ

Micro vacuum - All
162
13/162
1.16 ng/ft2
9.73 txg/ft2
1.51 jig/ft1
95% Chebyshev
(Mean, STD)
1.98 jig/ft2

Microvacuum -
Carpet
69
10/69
1 16 VJ-g/ft2
9.73 ^g/ft2
1.89 ^ig/ft2
95% Chebyshev
(Mean, STD)
2.94 M-g/ft2

Microvacuum -
Couch
78
3/78
1.16 p.g/ft2
3.6 ng/ft2
1.23 ng/ft2
95% Chebyshev
(Mean, STD)
1.41 |JLg/ft2

Wipe - All
114
57/114
0.25 ng/ft2
49.2 fig/ft2
1.75 jig/ft2
97.5%
Chebyshev
(Mean, STD)
4.59 ng/ft2

Wipe - Counter
32
15/32
0.25 ^g/ft2
7 M-g/ft2
1.17 ng/ft2
97.5%
Chebyshev
(Mean, STD)
3.07 |xg/ft2
¦"Minimum detected value includes values that may be Vx of the detection limit
Table 6-1
-------
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
a
Minimum*
Maximum
Statistic
UCL

Wipe - Floors
34
30/34
0.25 ng/ft2
49.2 ng/ft2
3.91 ng/ft2
97.5%
Chebyshev
(Mean, STD)
12.9 ng/ft2

Wipe - Walls
48
12/48
0.25 fig/ft2
4.48 fig/ft2
o.6i ng/ft2
95% Chebyshev
(Mean, STD)
1.18 ng/ft2
Dioxin (TEQ
EMPC
Wipe - All
114
88/114
0.475 ng/m2
1.66 ng/m2
0.644 ng/m2
95% Chebyshev
(Mean, STD)
0.693 ng/m2
(ND=l/2)
Wipe - Counter
32
23/32
0.475 ng/m2
0.823 ng/m2
0.641 ng/m2
95% H-UCL
0.669 ng/m2

Wipe - Floors
34
26/34
0.546 ng/m2
0.791 ng/m2
0.633 ng/m2
95% Chebyshev
(Mean, STD)
0.684 ng/m2

Wipe - Walls
48
39/48
0.518 ng/m2
1.66 ng/m2
0.653 ng/m2
95% Chebyshev
(Mean, STD)
0.756 ng/m2
PAH - TEF
Wipe - All
113
0/113
290 |xg/m2

Wipe - Counter
31
0/31
290 ng/m2

Wipe - Floors
34
0/34
290 ng/m2

Wipe - Walls
48
0/48
290 ng/m2

~Minimum detected value includes values that may be Vi of the detection limit
Table 6-1
-------
Table 6-2. Summary of the analytical results for the organic and inorganic compounds from the background study. The table presents the sample
size, frequency of detection, minimum and maximum detected concentrations, arithmetic mean, and the statistic used, and the upper confidence
limit (UCL) for each compound and matrix sampled. The values in this table were calculated using only the data sets from the residence areas for
each analyte.
Residential Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL
Asbestos
Bulk Dust
3
0/3
<0.5%

Air - PCM
50
21/50
0.0005 flee
0 007 f7cc
0.0014 Ccc
95% Chebyshev
(Mean, STD)
0.0023 f/cc

Air - TEM AHERA
48
2/48
0.0002 s/cc
0.0004 s/cc
0.00022 s/cc
95% Chebyshev
(Mean, STD)
0.00024 s/cc

Air - TEM PCMe
48
2/48
0.0002 s/cc
0.0004 s/cc
0.00022 s/cc
95% Chebyshev
(Mean, STD)
0.00024 s/cc

Micro vacuum - All
143
15/143
317 s/cm2
72,094 s/cm2
2,234 s/cm2

Micro vacuum - Carpet
60
10/60
317 s/cm2
72,094 s/cm2
2,861 s/cm2

Microvacuum - Couch
71
4/71
317 s/cm2
24,138 s/cm2
1,732 s/cm2

Microvacuum - Drapes
12
1/12
791 s/cm2
12,288 s/cm2
2,071 s/cm2
95% Chebyshev
(Mean, STD)
6,149 s/cm2

Wipe - All
104
14/104
592 s/cm2
83,893 s/cm2
2,309 s/cm2
95% Chebyshev
(Mean, STD)
6,192 s/cm2

Wipe - Ceiling
24
3/24
592 s/cm2
83,893 s/cm2
4,683 s/cm2
97.5% Chebyshev
(Mean, STD)
26,295 s/cm2
* Minimum detected value includes values that may be Vi of the detection limit
Table 6-2
-------
Residential Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Counter
25
3/25
592 s/cm2
2,770 s/cm2
870 s/cm2
95% Chebyshev
(Mean, STD)
1,357 s/cm2

Wipe - Floors
25
4/25
592 s/cm2
40,363 s/cm2
2,405 s/cm2
95% Chebyshev
(Mean, STD)
9,307 s/cm2

Wipe - Walls
30
4/30
592 s/cm2
12,267 s/cm2
1,530 s/cm2
95% Chebyshev
(Mean, STD)
3,473 s/cm2
MMVF
Bulk Dust
24
0/24
<0.5%

Air
48
1/48
0.032 s/L
0 216 s/L
0.041 s/L
95% Chebyshev
(Mean, STD)
0.06 s/L

Wipe - All
99
11/99
29 s/cm2
286 s/cm2
38 s/cm2
95% Chebyshev
(Mean, STD)
53 s/cm2

Wipe - Ceiling
23
1/23
29 s/cm2
286 s/cm2
40 s/cm2
95% Chebyshev
(Mean, STD)
87 s/cm2

Wipe - Counter
24
1/24
29 s/cm2
114 s/cm2
32 s/cm2
95% Chebyshev
(Mean, STD)
48 s/cm2

Wipe - Floors
24
8/24
29 s/cm2
172 s/cm2
52 s/cm2
95% Chebyshev
(Mean, STD)
89 s/cm2

Wipe - Walls
28
1/28
29 s/cm2
57 s/cm2
30 s/cm2
95% Chebyshev
(Mean, STD)
34 s/cm2
Lead
Bulk Dust
9
9/9
44.5 mg/kg
242 mg/kg
126 mg/kg
95% H-UCL
186 mg/kg
* Minimum detected value includes values that may be Vi of the detection limit
Table 6-2
-------
Residential Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Air
32
1/32
0.026 ng/m3
0.058 ng/m3
0.028 ng/m3
95% Chebyshev
(Mean, STD)
0.032 ng/m3

Microvacuum - All
144
12/144
1.16 ng/ft2
9.73 ng/ft2
1.53 jxg/ft2
95% Chebyshev
(Mean, STD)
2.05 ng/ft2

Microvacuum - Carpet
60
10/60
1.16 tig/ft2
9.73 tig/ft2
2.00 jag/ft2
95% Chebyshev
(Mean, STD)
3.20 ng/ft2

Microvacuum - Couch
72
2/72
1.16 ng/ft2
2.83 |jig/ft2
1.20 ng/ft2
95% Chebyshev
(Mean, STD)
1.34 jig/ft2

Microvacuum - Drapes
12
0/12
1.16 |ig/ft2

Wipe - All
80
39/80
0.25 ng/ft2
10.5 ng/ft2
1 04 ng/ft2
95% Chebyshev
(Mean, STD)
1.78 ng/ft2

Wipe - Counter
25
12/25
0.25 ng/ft2
5.9 jig/ft2
l.i ng/ft2
97.5% Chebyshev
(Mean, STD)
2.98 ng/ft2

Wipe - Floors
25
21/25
0.25 ^g/ft2
10.5 ng/ft2
1 82 tig/ft2
95% H-UCL
2.96 |j.g/ft2

Wipe - Walls
30
6/30
0.25 ^tg/ft2
1.01 ng/ft2
0.35 |ig/ft2
95% Chebyshev
(Mean, STD)
0.52 ng/ft2
Dioxin
Wipe - All
80
19/80
0.475 ng/m2
0.83 ng/m2
0.629 ng/m2
95% H-UCL
0.643 ng/m2

Wipe - Counter
25
6/25
0.475 ng/m2
0.823 ng/m2
0.639 ng/m2
95% H-UCL
0.672 ng/m2

Wipe - Floors
25
6/25
0.546 ng/m2
0.771 ng/m2
0.621 ng/m2
Student's t
0.643 ng/m2

Wipe - Walls
30
7/30
0.534 ng/m2
0.83 ng/m2
0 628 ng/m2
95% H-UCL
0.650 ng/m2
* Minimum detected value includes values that may be lA of the detection limit
Table 6-2
-------
Residential Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL
PAH
Wipe - All
80
0/80
290 ng/m2

Wipe - Counter
25
0/25
290 ng/m2

Wipe - Floors
25
0/25
290 (jig/m2

Wipe - Walls
30
0/30
290 p.g/m2

* Minimum detected value includes values that may be Zi of the detection limit
Table 6-2
-------
Table 6-3. Summary of the analytical results for the organic and inorganic compounds from the background study. The table presents the sample
size, frequency of detection, minimum and maximum detected concentrations, arithmetic mean, the statistic used, and the upper confidence limit
(UCL) for each compound and matrix sampled. The values in this table were calculated using only the data sets from the common areas for each
analyte.
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL
Asbestos
Bulk Dust
0

Air - PCM
14
10/14
0.0005 f/cc
0.007 tfcc
0.0028 f7cc
95%
Chebyshev
(Mean, STD)
0.0058 f/cc

Air - TEM AHERA
14
2/14
0.0002 s/cc
0.0004 s/cc
0.00024 s/cc
95%
Chebyshev
(Mean, STD)
0.00032 s/cc

Air - TEM PCMe
14
1/14
0.0002 s/cc
0.0004 s/cc
0.00023 s/cc
95%
Chebyshev
(Mean, STD)
0.00029 s/cc

Microvacuum - All
18
6/18
792 s/cm2
61,732 s/cm2
7,145 s/cm2

Microvacuum - Caipet
9
3/9
792 s/cm2
61,732 s/cm2
9,409 s/cm2

Microvacuum - Chair
3
1/3
1,979 s/cm2
22,952 s/cm2
8,970 s/cm2

Microvacuum - Couch
6
2/6
792 s/cm2
9,497 s/cm2
2,836 s/cm2

Wipe - All
42
11/42
592 s/cm2
3,798,910 s/cm2
123,507 s/cm2
97.5%
Chebyshev
(Mean, STD)
710,495 s/cm2
* Minimum detected value includes values that may be Vi of the detection limit
Table 6-3
-------
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Celling
8
1/8
592 s/cm2
5,916 s/cm2
1,492 s/cm2
95%
Chebyshev
(Mean, STD)
4,319 s/cm2

Wipe - Counter
7
3/7
592 s/cm2
1,183,205 s/cm2
170,193 s/cm2
99%
Chebyshev
(Mean, STD)
1,850,087
s/cm2

Wipe - Floors
9
4/9
592 s/cm2
3,798,910 s/cm2
423,979 s/cm2
99%
Chebyshev
(Mean, STD)
4,621,507
s/cm2

Wipe - Walls
18
3/18
592 s/cm2
149,055 s/cm2
9,344 s/cm2
97.5%
Chebyshev
(Mean, STD)
60,698 s/cm2
MMVF
Bulk Dust
0

Air
14
4/14
0.032 s/L
0.196 s/L
0.0452 s/L
95%
Chebyshev
(Mean, STD)
0.096 s/L

Wipe - All
42
3/42
29 s/cm2
286 s/cm2
39 s/cm2
95%
Chebyshev
(Mean, STD)
69 s/cm2

Wipe - Ceiling
8
0/8
29 s/cm2

Wipe - Counter
7
0/7
29 s/cm2

* Minimum detected value includes values that may be Yi of the detection limit
Table 6-3
-------
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Floors
9
3/9
29 s/cm2
286 s/cm2
76 s/cm2
95%
Chebyshev
(Mean, STD)
209 s/cm2

Wipe - Walls
18
0/18
29 s/cm2

Lead
Bulk Dust
0

Air
14
0/14
0.026 jig/m3
0.027 ng/m3
0 026 ^ig/m3
95%
Chebyshev
(Mean, STD)
0.027 jig/m3

Microvacuum - All
18
1/18
1.16 p-g/ft2
3.6 ng/ft2
1.30 p.g/ft2
95%
Chebyshev
(Mean, STD)
1.89 jig/ft2

Microvacuum - Carpet
9
0/9
1.16 ng/ft2

Microvacuum - Chair
3
0/3
1.16 |ig/ft2

Microvacuum - Couch
6
1/6
1.16 ng/ft2
3.6 ng/ft2
1.57 i-Lg/ft2
95%
Chebyshev
(Mean, STD)
3.34 jig/ft2

Wipe - All
34
18/34
0.25 jag/ft2
49.2 p-g/ft2
3.42 ng/ft2
97.5%
Chebyshev
(Mean, STD)
12.44 /ft2
* Minimum detected value includes values that may be 14 of the detection limit
Table 6-3
-------
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Counter
7
3/7
0.25 |j.g/ft2
7 Hg/ft2
1.39 ng/ft2
97.5%
Chebyshev
(Mean, STD)
7.28 ng/ft2

Wipe - Floors
9
9/9
2.3 jig/ft2
49.2 ng/ft2
9.74 (ig/fl2
95%
Chebyshev
(Mean, STD)
31.44 ng/ft2

Wipe - Walls
18
6/18
0.25 ^g/ft2
4.48 p.g/ft2
1.04 ij.g/ft2
97.5%
Chebyshev
(Mean, STD)
3.05 tig/fl2
Dioxin
Wipe - All
34
7/34
0.518 ng/m2
1.66 ng/m2
0.677 ng/m2
95%
Chebyshev
(Mean, STD)
0.817 ng/m2

Wipe - Counter
7
3/7
0.53 ng/m2
0.709 ng/m2
0.648 ng/m2
95%
Chebyshev
(Mean, STD)
0.767 ng/m2

Wipe - Floors
9
2/9
0.57 ng/m2
0.791 ng/m2
0.665 ng/m2
95% H-UCL
0.716 ng/m2

Wipe - Walls
18
2/18
0.518 ng/m2
1.66 ng/m2
0.694 ng/m2
95%
Chebyshev
(Mean, STD)
0.951 ng/m2
PAH
Wipe - All
33
0/33
290 jig/m2

Wipe - Counter
6
0/6
290 |ig/m2

* Minimum detected value includes values that may be /i of the detection limit
Table 6-3
-------
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Analyte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Floors
9
0/9
290 ng/m2

Wipe - Walls
18
0/18
290 ^g/m2

* Minimum detected value includes values that may be 'A of the detection limit
Table 6-3
-------
Table 6-4. Summary of the analytical results for the mineral compounds and total dust from the background study. The table presents the sample
size, frequency of detection, minimum and maximum detected concentrations, arithmetic mean, the statistic used, and the upper confidence limit
(UCL) for each compound and matrix sampled. The values in this table were calculated using the entire data set for each analyte, which includes
residential and common areas.
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL
Alpha-quartz
Bulk Dust
9
8/9
1.01 %
6.89 %
2.2 %
95% H-UCL
3.66 %

Air
46
12/46
2 pg/m3
259 pg/m3
9.2 pg/m3
95% Chebyshev (Mean, STD)
33.5 pg/m3

Wipe - All
114
51/114
12.5 pg/ft2
1880 pg/ft*
79.5 pg/ft2
95% Chebyshev (Mean, STD)
156.3 pg/ft2

Wipe - Counter
32
13/32
12.5 M-g/ft2
370 jig/ft2
67.0 pg/ft2
95% Chebyshev (Mean, STD)
134.7 pg/ft2

Wipe - Floors
34
20/34
25 pg/ft2
1880 |JLg/ft2
125.4 pg/ft2
95% Chebyshev (Mean, STD)
367.9 pg/ft2

Wipe - Walls
48
18/48
12.5 pg/ft2
270 pg/ft2
55.3 pg/ft2
95% Chebyshev (Mean, STD)
94.1 pg/ft2
Calcite
Bulk Dust
9
1/9
0.425 %
4.95 %
1.56%
95% H-UCL
3.41 %

Air
46
0/46
8 pg/m3
11 pg/m3
8.8 pg/m3
95% Chebyshev (Mean, STD)
9.3 tig/m3

Wipe - All
114
3/114
50 pig/ft2
785 pg/ft2
102.6 ^g/fl2
95% Chebyshev (Mean, STD)
132.3 pg/ft2

Wipe - Counter
32
0/32
50 pg/ft2
100 pg/ft2
92.2 pg/ft2
95% Chebyshev (Mean, STD)
106.4 pg/ft2

Wipe - Floors
33
2/33
50 ^xg/ft2
350 pg/ft2
104.8 M-g/ft2
95% Chebyshev (Mean, STD)
147.2 pg/ft2

Wipe - Walls
49
1/49
50 jj-g/ft2
785 pg/ft2
107.9 pg/ft2
95% Chebyshev (Mean, STD)
170.2 ng/ft2
Cristobal ite
Bulk Dust
9
0/9
0.04 %
4.95 %
1.45%
97.5% Chebyshev (Mean, STD)
4.69 %

Air
46
0/46
8 pg/m3
11 pg/m3
8.8 pg/m3
95% Chebyshev (Mean, STD)
9.3 pg/m3
* Minimum detected value includes values that may be Vx of the detection limit
Table 6-4
-------
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - All
114
1/114
50 jxg/ft2
260 M-g/ft2
93.9 Mg/ft2
95% Chebyshev (Mean, STD)
103.7 Mg/ft2

Wipe - Counter
32
0/32
50 ng/ft2
100 M-g/ft2
92.2 Mg/ft2
95% Chebyshev (Mean, STD)
106.4 Mg/ft2

Wipe - Floors
33
1/33
50 jig/ft2
260 Mg/ft2
97.3 Mg/ft2
95% Chebyshev (Mean, STD)
123.4 Mg/ft2

Wipe - Walls
49
0/49
50 M-g/ft2
100 Mg/ft2
92.9 Mg/ft2
95% Chebyshev (Mean, STD)
103.9 Mg/ft2
Gypsum
Bulk Dust
9
1/9
0.02 %
2.38 %
0.76 %
97.5 Chebyshev (Mean, STD)
2.33 %

Air
46
0/46
4 ng/m3
5.5 ng/m3
4.25 Mg/m3
95% Chebyshev (Mean, STD)
4.54 Mg/m3

Wipe - All
114
0/114
25 fig/ft2
50 jig/ft2
46.3 Mg/ft2
95% Chebyshev (Mean, STD)
49.9 M-g/ft2

Wipe - Counter
32
0/32
25 jig/ft2
50 Mg/ft2
46.7 Mg/ft2
95% Chebyshev (Mean, STD)
53 2 Mg/ft2

Wipe - Floors
33
0/33
25 Mg/ft2
50 Mg/ft2
46.2 Mg/ft2
95% Chebyshev (Mean, STD)
53.1 Mg/ft2

Wipe - Walls
49
0/49
25 ^g/ft2
50 Mg/ft2
46.4 Mg/ft2
95% Chebyshev (Mean, STD)
51.9 Mg/ft2
Portlandite
Bulk Dust
9
0/9
0.04 %
4.95 %
1.45%
97.5% Chebyshev (Mean, STD)
4.69 %

Air
46
0/46
8 ng/m3
11 pg/m3
8.8 ng/m3
95% Chebyshev (Mean, STD)
9.3 Mg/m3

Wipe - All
114
0/114
50 tig/ft2
100 M-g/ft2
92.5 Mg/ft2
95% Chebyshev (Mean, STD)
99.8 Mg/ft2

Wipe - Counter
32
0/32
50 Mg/ft2
100 M-g/ft2
92.2 Mg/ft2
95% Chebyshev (Mean, STD)
106.4 pg/ft2

Wipe - Floors
33
0/33
50 M-g/ft2
100 Mg/ft2
92.4 Mg/ft2
95% Chebyshev (Mean, STD)
106.2 pg/ft2

Wipe - Walls
49
0/49
50 ng/ft2
100 Mg/ft2
92.9 Mg/ft2
95% Chebyshev (Mean, STD)
103.9 pg/ft2
Tridymite
Bulk Dust
9
0/9
0.04 %
4.95 %
1.45%
97.5% Chebyshev (Mean, STD)
4.69 %
* Minimum detected value includes values that may be !/z of the detection limit
Table 6-4
-------
Total Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
ii
Minimum*
Maximum
Statistic
UCL

Air
46
0/46
8 M-g/m3
11 jig/m3
8.8 tig/m3
95% Chebyshev (Mean, STD)
9.3 ng/m3

Wipe - All
114
0/114
50 |ig/ftz
100 jig/ft2
92.5 Mg/ft2
95% Chebyshev (Mean, STD)
99.8 ng/ft2

Wipe - Counter
32
0/32
50 jag/ft2
100 jig/ft2
92.2 tig/ft2
95% Chebyshev (Mean, STD)
106.4 M-g/ft2

Wipe - Floors
33
0/33
50 ng/ft2
100 M-g/ft2
92.4 Mg/ft2
95% Chebyshev (Mean, STD)
106.2 M-g/ft2

Wipe - Walls
49
0/49
50 ng/ft2
100 M-g/ft2
92.9 Mg/ft2
95% Chebyshev (Mean, STD)
103.9 jig/ft2
Total Dust
Wipe
35
35/35
0.366 mg/ft2
18.1 mg/ft2
10.9 mg/ft2
95% Chebyshev (Mean, STD)
14.4 mg/ft2
* Minimum detected value includes values that may be Vi of the detection limit
Table 6-4
-------
Table 6-5. Summary of the analytical results for the mineral compounds and total dust from the background study. The table presents the sample
size, frequency of detection, minimum and maximum detected concentrations, arithmetic mean, the statistic used, and the upper confidence limit
(UCL) for each compound and matrix sampled. The values in this table were calculated using only the data sets from the residence areas for each
analyte.
Residential Data Set
n
Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
Minimum*
Maximum
Statistic
UCL
Alpha-quartz
Bulk Dust
9
8/9
1.01 %
6.89 %
2.2 %
95% H-UCL
3.66 %

Air
32
8/32
2 M-g/m3
259 ng/m3
11 8 jig/m3
97.5% Chebyshev
(Mean, STD)
61.9 pg/m3

Wipe - All
81
31/81
12.5 >ig/ft2
370 jj-g/ft2
50.8 ng/ft2
95% Chebyshev
(Mean, STD)
79.6 pg/ft2

Wipe - Counter
25
10/25
12.5 ng/ft2
370 |jtg/fl2
67.5 ng/ft2
95% Chebyshev
(Mean, STD)
148.4 |^g/fl2

Wipe - Floors
26
13/26
25 M-g/ft2
180 tig/ft2
54.0 pg/ft2
95% Chebyshev
(Mean, STD)
91 1 pg/ft2

Wipe - Walls
30
8/30
12.5 jxg/ft2
110 ng/ft2
34.2 pg/ft2
95% Chebyshev
(Mean, STD)
51.6 pg/ft2
Calcite
Bulk Dust
9
1/9
0.425 %
4.95 %
1.56%
95% H-UCL
3.41 %

Air
32
0/32
8 p.g/m3
11 pg/m3
8.78 pg/m3
95% Chebyshev
(Mean, STD)
9.4 pg/m3

Wipe - All
80
2/80
50 ng/ft2
785 M-g/ft2
104.2 |j.g/fl2
95% Chebyshev
(Mean, STD)
145.2 jig/ft2
* Minimum detected value includes values that may be Vi of the detection limit
Table 6-5
-------
Residential Data Set
n
Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
Minimum*
Maximum
Statistic
UCL

Wipe - Counter
25
0/25
50 p.g/ft2
100 ng/ft2
92 ng/ft2
95% Chebyshev
(Mean, STD)
108.3 jig/ft2

Wipe - Floors
24
1/24
50 ng/ft2
350 ng/ft2
102.1 ng/ft2
95% Chebyshev
(Mean, STD)
152.0 jxg/ft2

Wipe - Walls
31
1/31
50 ng/ft2
785 ng/ft2
115.6 ^g/ft2
95% Chebyshev
(Mean, STD)
213.8 jag/ft2
Cristobalite
Bulk Dust
9
0/9
0.04 %
4.95 %
1.45%
97.5% Chebyshev
(Mean, STD)
4.69 %

Air
32
0/32
8 ng/m3
11 n.g/mJ
8.78 ^.g/m3
95% Chebyshev
(Mean, STD)
9.4 ng/m3

Wipe - All
80
0/80
50 jig/ft2
100 tig/ft2
91.9 ^g/ft2
95% Chebyshev
(Mean, STD)
100.9 M-g/ft2

Wipe - Counter
25
0/25
50 (xg/ft2
100 ng/ft2
92 0 ng/ft2
95% Chebyshev
(Mean, STD)
108.3 fig/ft2

Wipe - Floors
24
0/24
50 ng/ft2
100 jig/ft2
91.7 ng/ft2
95% Chebyshev
(Mean, STD)
108.6 p-g/fl2

Wipe - Walls
31
0/31
50 ng/ft2
100 ng/ft2
91.9 ng/ft2
95% Chebyshev
(Mean, STD)
106.6 ^g/ft2
Gypsum
Bulk Dust
9
1/9
0.02 %
2.38 %
0.76 %
97.5% Chebyshev
(Mean, STD)
2.33 %
* Minimum detected value includes values that may be XA of the detection limit
Table 6-5
-------
Residential Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Air
32
0/32
4 ng/m3
5 5 M-g/m3
4.23 M^g/m3
95% Chebyshev
(Mean, STD)
4.59 jig/m3

Wipe - AH
80
0/80
25 M-g/ft2
50 ng/ft2
45.9 fig/ft2
95% Chebyshev
(Mean, STD)
50.5 fig/ft2

Wipe - Counter
25
0/25
25 tig/ft2
50 ^g/ft2
46.0 |ig/ft2
95% Chebyshev
(Mean, STD)
54.2 |Jtg/ft2

Wipe - Floors
24
0/24
25 iig/ft2
50 ng/ft2
45.8 ng/ft2
95% Chebyshev
(Mean, STD)
54.3 ^g/ft2

Wipe - Walls
31
0/31
25 vig/ft2
50 |j.g/ft2
46.0 fig/ft2
95% Chebyshev
(Mean, STD)
53.3 ^g/ft2
Portlandite
Bulk Dust
9
0/9
0 04 %
4.95 %
1.45 %
97.5% Chebyshev
(Mean, STD)
4.69 %

Air
32
0/32
8 ^g/m3
11 ^g/m3
8.78 ng/m3
95% Chebyshev
(Mean, STD)
9.4 fxg/m3

Wipe - All
80
0/80
50 |ig/ft2
100 ng/ft2
91.9 ng/ft2
95% Chebyshev
(Mean, STD)
100.9 jig/ft2

Wipe - Counter
25
0/25
50 ng/ft2
100 jig/ft2
92.0 ng/ft2
95% Chebyshev
(Mean, STD)
108.3 fig/ft2

Wipe - Floors
24
0/24
50 jig/ft2
100 jig/ft2
91.7 jig/ft2
95% Chebyshev
(Mean, STD)
108.6 ng/ft2
* Minimum detected value includes values that may be Zi of the detection limit
Table 6-5
-------
Residential Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - Walls
31
0/31
50 |xg/ft2
100 ng/ft2
91.9 ng/ft2
95% Chebyshev
(Mean, STD)
106.6 ng/ft2
Tridymite
Bulk Dust
9
0/9
0.04 %
4.95 %
1.45%
97.5% Chebyshev
(Mean, STD)
4.69 %

Air
32
0/32
8 p-g/m3
11 (ig/m3
8.78 p.g/m3
95% Chebyshev
(Mean, STD)
9.4 jig/m3

Wipe - All
80
0/80
50 ng/ft2
100 jig/ft2
91.9 n-g/ft2
95% Chebyshev
(Mean, STD)
100.9 ^g/ft2

Wipe - Counter
25
0/25
50 (ig/ft2
100 M-g/ft2
92.0 >ig/ft2
95% Chebyshev
(Mean, STD)
108.3 |ag/ft2

Wipe - Floors
24
0/24
50 ng/ft2
100 ng/ft2
91.7 (ig/ft2
95% Chebyshev
(Mean, STD)
108.6 ^ft2

Wipe - Walls
31
0/31
50 jig/ft2
100 ^ft2
91.9 ng/ft2
95% Chebyshev
(Mean, STD)
106.6 jig/ft2
Total Dust
Wipe
26
26/26
0.366 mg/ft2
18.1 mg/ft2
10.7 mg/ft2
95% Chebyshev
(Mean, STD)
15.0 mg/ft2
* Minimum detected value includes values that may be 14 of the detection limit
Table 6-5
-------
Table 6-6. Summary of the analytical results for the mineral compounds and total dust from the background study. The table presents the sample
size, frequency of detection, minimum and maximum detected concentrations, arithmetic mean, the statistic used, and the upper confidence limit
(UCL) for each compound and matrix sampled. The values in this table were calculated using only the data sets from the common areas for each
analyte.
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL
Alpha-quartz
Bulk Dust
0

Air
14
4/14
2 |ig/m3
9 lig/m3
3.14 jxg/m3
95% Chebyshev (Mean, STD)
5.64 ng/m3

Wipe - AH
33
20/33
12.5 ^g/ft2
1880 ^g/ft2
149.9 jig/ft2
97.5% Chebyshev (Mean, STD)
508.5 jig/ft2

Wipe - Counter
7
3/7
12.5 jj-g/fl2
220 jig/ft2
65.4 ng/ft2
95% H-UCL
288.5 jig/ft2

Wipe - Floors
8
7/8
25 |ig/ft2
1880 jig/fl2
357.5 M-g/ft2
97.5% Chebyshev (Mean, STD)
1769.4 ng/ft2

Wipe - Walls
18
10/18
25 ng/ft2
270 ^g/ft2
90.6 p.g/ft2
95% Chebyshev (Mean, STD)
180.1 pg/fl2
Calcite
Bulk Dust
0

Air
14
0/14
8 ng/m3
10 fxg/m3
8.86 ng/m3
95% Chebyshev (Mean, STD)
9.75 jig/m3

Wipe - All
34
1/34
50 j-Lg/ft2
260 ng/ft2
98.8 ^g/ft2
95% Chebyshev (Mean, STD)
123.4 tig/ft2

Wipe - Counter
7
0/7
50 ng/ft2
100 ng/ft2
92 9 |ag/fl2
95% Chebyshev (Mean, STD)
124.0 |j.g/ft2

Wipe - Floors
9
1/9
50 (j-g/ft2
260 iJig/ft2
112.2 M-g/ft2
95% Chebyshev (Mean, STD)
196.2 M-g/ft2

Wipe - Walls
18
0/18
50 |ag/ft2
100 M-g/ft2
94.4 ng/ft2
95% Chebyshev (Mean, STD)
111.1 vg/R2
Cristobalite
Bulk Dust
0

Air
14
0/14
8 tig/m3
10 |ig/m3
8.86 ng/m3
95% Chebyshev (Mean, STD)
9.75 |i.g/m3
* Minimum detected value includes values that may be Vz of the detection limit
Table 6-6
-------
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Wipe - All
34
1/34
50 M-g/ft2
260 ^ig/ft2
98.8 |ag/ft2
95% Chebyshev (Mean, STD)
123.4 ng/ft2

Wipe - Counter
7
0/7
50 ng/ft2
100 jig/ft2
92.9 ng/ft2
95% Chebyshev (Mean, STD)
124.0 ng/ft2

Wipe - Floors
9
1/9
50 ^g/ft2
260 ^g/ft2
112.2 jig/ft2
95% Chebyshev (Mean, STD)
196.2 ^ft2

Wipe - Walls
18
0/18
50 ^g/ft2
100 ^g/ft2
94.4 jig/ft2
95% Chebyshev (Mean, STD)
111.1 ng/ft2
Gypsum
Bulk Dust
0

Air
14
0/14
4 ng/m3
5 Hg/m3
4.29 ng/m3
95% Chebyshev (Mean, STD)
4.83 M-g/m3

Wipe - All
34
0/34
25 [ig/ft2
50 fig/ft2
47.1 ng/ft2
95% Chebyshev (Mean, STD)
53.2 ng/ft2

Wipe - Counter
7
0/7
25 ng/ft2
50 \ig/ft2
46.4 jig/ft2
95% Chebyshev (Mean, STD)
62.0 ^g/ft2

Wipe - Floors
9
0/9
25 ng/a2
50 n-g/ft2
47.2 iig/ft2
95% Chebyshev (Mean, STD)
59.3 M-g/fl2

Wipe - Walls
18
0/18
25 ng/ft2
50 ng/ft2
47.2 txg/fl2
95% Chebyshev (Mean, STD)
55.5 jig/ft2
Portlandite
Bulk Dust
0

Air
14
0/14
8 ng/m3
10 ng/m3
8.86 ng/m3
95% Chebyshev (Mean, STD)
9.75 jig/m3

Wipe - All
34
0/34
50 M.g/ft2
100 *ig/ft2
94.1 pg/ft2
95% Chebyshev (Mean, STD)
106.3 ng/ft2

Wipe - Counter
7
0/7
50 ng/ft2
100 jj.g/ft2
92.9 ng/ft2
95% Chebyshev (Mean, STD)
124.0 [ig/ft2

Wipe - Floors
9
0/9
50 ng/ft2
100 ng/ft2
94.4 ng/ft2
95% Chebyshev (Mean, STD)
118.7 ng/ft2

Wipe - Walls
18
0/18
50 Hg/ft2
100 ng/ft2
94.4 jig/fl2
95% Chebyshev (Mean, STD)
111.1 \ig/R2
Tndymite
Bulk Dust
0

* Minimum detected value includes values that may be Vz of the detection limit
Table 6-6
-------
Common Area Data Set

Freq. Of
Detection
Range
Arithmetic
Mean

Anaylte
Matrix
n
Minimum*
Maximum
Statistic
UCL

Air
14
0/14
8 ng/m3
10 tig/m3
8.86 jig/m3
95% Chebyshev (Mean, STD)
9.75 iig/m3

Wipe - All
34
0/34
50 ng/ft2
100 j-ig/ft2
94.1 ^g/ft2
95% Chebyshev (Mean, STD)
106.3 jig/ft2

Wipe - Counter
7
0/7
50 jig/ft2
100 ng/ft2
92.9 fig/ft2
95% Chebyshev (Mean, STD)
124.0 jig/ft2

Wipe - Floors
9
0/9
50 ng/ft2
100 p-g/ft2
94.4 p.g/ft2
95% Chebyshev (Mean, STD)
118.7 ng/ft2

Wipe - Walls
18
0/18
50 jig/ft2
100 |ig/ft2
94.4 [ig/ft2
95% Chebyshev (Mean, STD)
111.1 jig/ft2
Total Dust
Wipe
9
9/9
5.3 mg/ft2
17.5 mg/ft2
10.7 mg/ft2
95% Chebyshev (Mean, STD)
17.2 mg/ft2
* Minimum detected value includes values that may be XA of the detection limit
Table 6-6
-------
Table 7-1. Summary of U.S. Residential Building Average Indoor Airborne Asbestos
Concentrations for Asbestos Fibers > 5 Long by Direct Transmission Electron Microscopy
Site Description
Number
of
Samples
Asbestos Fibers > 5 Long
(f/cc)
Reference
Range
Mean
15 San Francisco
residences (houses) with
ACM
30
ND
ND
CPSC1987
15 Cleveland residences
(houses) with ACM
30
ND - 0.002
0.00023
CPSC1987
15 Philadelphia
residences (houses) with
ACM
29
ND - 0 001
0.00007
CPSC 1987
10 residential building
10
-
0.00000
Lee et al. 1992
1 San Francisco area
residential building
sampled following the
1989 Loma Prieta
earthquake
2

0.00213
Van Orden et al.
1995
Source: Adapted from HEI (1991), ATSDR (2001), Van Orden et al. (1995)
ACM = asbestos-containing material; ND = non-detect
-------
Table 7-2. Summary of Settled Asbestos Surface Dust Loadings Determined Through
Microvacuum Sampling and Indirect Analysis by Transmission Electron Microscopy
Building
Category
Number of
Buildings
Number of
Samples
Surface Loading of Asbestos Structures
(s/cm2)

Range
Geometric Mean
Outside buildings
in a large city
5
79
<400 to 140,000
5100
Inside buildings
with no surfacing
ACM
6
28
<240 to 210,000
1000
Areas of
buildings with
acoustical plaster
12
34
<3500 to 74 million
160,000
Source: Ewing (2000).
ACM = asbestos-containing material
-------
Table 7-3. Household Dust Lead Measurements from Wipe Sampling in an Old, Urban
Community
Sample
Collection
Site
Number of
Samples (see
note below)
Median
Range
EPA
Standard
Percentage
above
standard
(J^g/ft2)
(ng/ft2)
Wft2)
Non-carpeted
floors
124
12
3-369
40
23
Carpeted
floors
65
5
3-78
40
5

Source. Galhcchio et al. (2002)
Note: Each reported sample was a composite of wipe samples taken from three different rooms.
-------
Table 7-4. Estimated Distribution of Lead Loadings (ug/ft2) In U.S. Housing
Uncarpeted Floors, By Census Region and Building Age Category (source: HUD 2001)
Will
Age,bf Housing
tv ' f
Ii'Jl'A
n VT"r"'s 5
mean?
fJdf
m
«!KCVV •
i f\
?";v«r; ;1
rstderr 1
-*r- .¦ .
; max
¦r ¦-
P9.9

(5.V
4 P90'
!'4Q3';
median
. r
c
: <)i.
,.rs 1
min
(detection
' rate
' ' % '^
nondetects
Northeast
1978 - 1998
92
1 6
194
35
11 8
3 76e+02?
025
11 0
11 0
55
30? 16
1 0
08
0 81
08
21 / 92
77%
Northeast
1960-1977 i 79 I 5 11 193 1
75
38 2i 3 73e+04{
20!
1296
129 6 j 80? 60S 30| 1 0J 0 S| 08*
08
30/79
62%
Northeast
1946-1959 \ 68 i 3 11 40 8
24
13 1
1 66e+031
0 5i
17 0 j 170
15 0g 9 0j 30j 12
0 8 > 08*
08
30/68
56%
Northeast
1940-1945 * 38
53
1 80 9
45
152J 6 55e+03!
1 3?
75 0* 75 01 13 of lOOj 7 0^ 4 1
10' 0 8^
0 8
23/38
39%
Northeast
<=1939
155
24 0
1765 8
12 21 73 7
3 t2e+06'
12 9'"
1845 0
128 0
56 7
31 0! 90
40
1 44 0 8
0 8
111 /155
28%
Midwest
1978-1998 ! 87
1 5
188
4 6 j 12 5' 3 52e+02 \
02?
18 Of 965 40? 30: 1 6® 08
0 8? 08'
0 8
16/87
82%
M idwest
1960-1977
133
2 8J 7401 55
26 2"
5 47c+03 i
06
720} 22 0J 12 li 5 0! 2 0^
1 0
08'
0 8,
0 8
45/ 133
66%
Midwest
1946-1959
85
84
210 9 j 43
25 I5
4 45e+04 f
20
105 0j 910? 52 0' 180
5 01 20
1 0
08 ,
08
47/85
45%
Midwest J 1940-1945
25
15 11 26981 26,
17 83
7 28e+045
43'
92 0
92 0| 710,
33 2,' 20 8- 10 2
1 0
08
08
15/25
40%
Midwest
<= 1939
124
56 4
4087 2'
10 9>
72 5!
1 67e+07 i
37 8'
4830 0
386 o|
107 0t
47 0
15 0" 50
0 8,
08
0 8
92 / 124
26%
South $ 1978 -1998
196
20
2000
99
994'
4 00e+04'
1 ll
556 0'
90
50
305
1 6t 08
08.
08!
08
77
71%
South j 1960-1977
223
1 7
25 8 j 54
1
153
6 65e+02;
0 2 *
28 0
12 0
oj
3 o'
1 6* 1 0i 0 8]
08-
08
79
77
South 1 1946 -1959
125 ,
70
378 8
10 8'
54 5;
1 44e+05j
32;
315 0*
315 Oj
14 OS
60?
3 0
12
0 8|
0 8''
08
77
77
South
1940-1945 "
43
48
88 1
3 Si
183S
7 77e+03l
1 2
56 0_
56 0;
17 oj
90?
50
25
1 2;
08
08
77
77
South
<=1939
80
172
479 3
39i
27 8>
2 30e+05 ?
5 1 '
404 3-
233 0;
60 0f
32 l"
I20:
40;
1 8
0 8
0 8
77
77
West
1978-1998
115
27
233 6 j
10 71
85 5 i
5 46e+04(
2 0'
2760;
10 oj
30J
1 6
1 05
08?
08;
0 8
08
77
77
West
1960- 1977
195
1 6
11 s!
27!
72!
1 32e+02{
0 1
11 0>
60
4 01
3 0!
20;
1 0S
084
08
08
77
77
West
1946- 1959
77
39
62 3:
40!
16 Oi
3 88e+03*
08
470*
39 oi
15 0|
9 0;
30,
15;
09:
08
08
77
77
West
1940 - 1945
21
40
34 11
0 9]
8 5'
1 16e+03,
07'
90'
90
90;
90;
70.
40
1 5
0 8.
0 8
77
77
West
<= 1939
39 .
50
.83?j
3 M
16 7'
7 05e+03s
1 2 .
41 0(
41 ot
27 0'
11 OS'
40
2 1
1 1
0 8
0 8
77
77
-------
^able 7-5. Background Soil Concentrations of Polycyclic Aromatic Hydrocarbons (PAHs)
Concentrations (pg/kg)
Compound
Rural soil
Agricultural Soil
Urban Soil
Acenaphthene
1.7
6

Acenaphthylene

Anthracene

11-13

Benzo(a)an1tiracena
S-20
56-110
169-59,000
Benzo(a)pyrene
2-1,300
4.6-900
165-220
Ben20(b)f luo ra nthene
20-30
58-220
15,000-62,000
Ben20(e)pyrene

53-130
60-14,000
Ben2o(g,h,i)pe rylene
10-70
66
900-47,000
Benzo(k)fluorantlwie
10-110
58-250
300-26,000
Ch/ysene
38.3
78-120
251-640
Fluoranttiene
0.3—40
120-210
200-166,000
Fluorene

9.7

ldeno(1,253-c,d)pyrene
10-15
63-100
8,000-61,000
Fhenanlhrene
30.0
48-140

Pyrene
1-19.7
99-150
145-147,000
aDenved Irom:
1ARC 1973
While and Vanderslice 1980
Windsor and Hrtes 1979
Edwards 1983
Butler et a). 1984
Vogt et al. 1987
Jones et al. 1987
Source. ATSDR(1995)
-------
Table 8-3. An evaluation was conducted 10 detenrime how the estimated UCLs were effected by assigning 1/2 of the
detection limit for samples thai were below the detection limit (DL) In general, the variation between the differenl
melhods (i e., ND=0, ND=1 2, and ND=DL) aTe directly related to the frequency of detection, As illustrated below,
the lower the frequency of detection, the greater the variability, with values ranging from 100% less to 100% greater
for data sets thai contained a!! values below the detection limit The use of 1/2 of the detection limit results in a mid-
point estimate.
Analyte
Surface
Freq. Of
ND=0
ND=l/2
ND=DL
Percent Difference
Percent Difference
Detection (%)
UCL
UCL
UCL
ND=0/ND=l/2
ND=DL/ND=l/2
Lead
Bulk Dust
100%
186
186
186
0%
0%
Total Dust
Hard Surface
100%
144
144
14 4
0%
0%
Lead
Hard Surface
49%
I 69
1 78
1 88
-5%
5%
Asbestos
PCM - Air
42%
0 0022
00023
0 0025
-6%
7%
Alpha-quartz
Hard Surface
38%
68 3
79 6
91 8
-14%
15%
Asbestos
Hard Surface
13%
5,462
6,192
6,965
-12%
12%
MMVF
Hard Surface
10%
29
52
76
-44%
46%
MMVF
Air
8%
0 034
0 060
0 088
-44%
45%
Lead
Porous Surface
8%
1 00
1 98
2 95
-49%
49%
Asbestos
PCMe
5%
0 00007
0 00024
0 00044
-72%
80%
Asbestos
TEM AHERA - Air
4%
0 00007
0 00024
0 00043
-72%
80%
Calcite
Hard Surface
3%
60 8
132 3
232 3
-54%
76%
Lead
Air
2%
0 0068
0 0304
00549
-78%
81%
Cnstobalite
Hard Surface
1%
12 2
103 7
200 5
-S8%
93%
Calcite
Air
0%
0
93
18.6
-100%
100%
Cnstobalite
Air
0%
0
9.3
18.6
-100%
100%
Gypsum
Air
0%
0
93
18.6
-100%
100%
Gypsum
Hard Surface
0%
0
49.9
99.8
-100%
100%
Portlandite
Air
0%
0
9.3
18.6
-100%
100%
Portlandite
Bulk Dust
0%
0
4.69
937
-100%
100%
Portlandite
Hard Surface
0%
0
99.8
199.7
-100%
100%
Tndynute
Air
0%
0
9J
18.6
-100%
100%
Tndynute
Bulk Dust
0%
0
4 69
9.37
-100%
100%
Tndymite
Hard Surface
0%
0
99.8
199.7
-100%
100%
These data sets were not included in the above table because the frequency of detection or the variability in the three values that were
calculated were altered by additional factors, thus they are reported separately
'These values are also influenced by a change in distribution from either non-parametric to lognormal or lognormal to non-parametric due to
altering the values between ND=0, ND=l/2, and ND=DL This required different statistical methods to be used which resulted in the
comparison of the three values not being similar to comparing values that were calculated using the same statistic
{These values are also influenced by the way that the frequency of detection is calculated, as there are 17 differenl dioxin congeners This
results in the comparison with Lhe other data being dissimilar as they are based on the frequency of detection of a single compound For
example, one sample may have detected one congener, while a second sample detected 15 congeners Each sample would be considered to
be above the detection limit, however the values used to estimate the UCL would be altered for 16 congeners in one sample but only for 2
congeners ui the second sample, thus creating greater vanbility from the other data sets
These values are also influenced by a change in variability within the data set due to altering the values between ND=0, ND=l/2, and
ND=DL This changed the standard deviation of the data set which required a different confidence interval to be used to estimate the UCL
The comparison of values that use different confidence intervals resulted in the comparison nol being similar to the other data sets
Analyte
Surface
Freq. Of
Detection (%)
ND=0
UCL
ND=J/2
UCL
ND=DL
UCL
Percent Difference
ND=0/ND=l/2
Percent Difference
ND=DUND=lrt
Alpha-quartz
Bulk Dust1
89%
366
4 97
6%
36%
Dioxin
Hard Surface}
77%
0 087
0 693
330
-87%
92%
Alpha-quartz
Air*
25%
45 5
61 9
48 0
-26%
-22%
Calcite
Bulk Dust1
11%
0 61
341
7 05
-82%
107%
Gypsum
Bulk Dust
11%
i 42
2 33
471
-39%
102%
Cnslobalite
Bulk Dust
0%
4.69
10 70
-100%
J 28%
-------
-------
E
-------
ATTACHMENT A
World Trade Center Indoor Air Assessment:
Selecting Contaminants of Potential Concern
and
Setting Health-Based Benchmarks
-------
World Trade Center Indoor Air Assessment:
Selecting Contaminants of Potential Concern
and
Setting Health-Based Benchmarks
Prepared by the Contaminants of Potential Concern (COPC) Committee
of the World Trade Center Indoor Air Taskforce Working Group
Contributors:
U.S Environmental Protection Agency New York City Department of Health
Mark Maddaloni Nancy Jeffery
Peter Grevatt Ken Carhno
Terry Smith Jeanine Prudhomme
Dore LaPosta Chris D'Andrea
Charles Nace Vince Colucci
John Schaum Caroline Bragdon
DanaTulis James Miller
Agency for Toxic Substances and Disease Registry
Sven Rodenbeck
Danielle Devoney
New York State Department of Health
Occupational S
David Ippolito
Dan Crane
-------
Peer Review Draft (September, 2002)
Table of Contents
Introduction 4
Selecting the Contaminants of Potential Concern (COPCs) 4
Lead and Combustion By-Products (PAHs, Dioxin) 5
Lead 5
PAHs 6
Dioxin 6
Building Materials (Asbestos, Fibrous Glass, Crystalline Silica) 6
Asbestos .7
Fibrous Glass 7
Crystalline Silica 7
Other Substances that Were not Selected to be COPCs 9
Setting Benchmarks for the Contaminants of Potential Concern (COPCs) 10
Developing Risk-Based Criteria for Indoor Air 11
Developing Risk-Based Criteria for Settled Dust 13
Developing Benchmark Levels Based on Occupational Health Standards 15
References 27
APPENDIX A
Hazardous Substances Not Included in Indoor Environment Sampling Program 1
APPENDIX B
World Trade Center Health Effects Screening Criteria for Ambient Air 1
APPENDIX C
Basis for Tier III screening level of 1 E-04 1
APPENDIX D
Assessing Exposures to Indoor Air and to Residues on Indoor Surfaces 1
APPENDIX E
IEUBK Model Results for Lead in Air 1
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Tables
Table 1. Index of NIOSH and OSHA exposure limits and estimated maximum values in Lower
Manhattan 8
Table 2 Exposure parameters for calculating clearance criteria for air samples 12
Table 3. Exposure parameters used to calculate clearance criteria for wipe samples 14
Table 4. Lead 17
Table 5. Polycyclic Aromatic Hydrocarbons (PAHs) 18
Table 6. Dioxin 19
Table 7. Asbestos 21
Table 8. Fibrous Glass 23
Table 9. Crystalline silica - respirable fraction of alpha-quartz 25
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World Trade Center Indoor Air Assessment:
Selecting Contaminants of Potential Concern
And Setting Health-Based Benchmarks
Introduction
Since September 11, 2001, the outdoor environment around the World Trade Center (WTC) site
and nearby areas has been extensively monitored by a group of federal, state, and local agencies1.
The agencies have taken samples of the air, dust, water, river sediments and drinking water and
analyzed them for the presence of pollutants that might pose a health risk to response workers at
the WTC site, office workers, and local residents. While some people may have experienced
acute irritant and respiratory effects from the collapse of the towers and associated fires,
extended monitoring of the ambient air at and beyond the perimeter of the WTC site over the
past year indicates that contaminant concentrations pose a low risk of long-term health effects.
During this same time period, limited investigation of the indoor environment in residential
dwellings has occurred [NYCDOH, 2002; Chatfield & Kominsky, 2001] As the cleanup of the
WTC site is coming to an end, governmental health and environmental agencies are directing
resources to evaluate the indoor environment for the presence of pollutants that might pose
long-term health nsks to local residents. Selecting Contaminants of Potential Concern (COPCs)
and setting health-based benchmarks will assist the Pilot Cleaning Effectiveness Initiative2 and
inform the selection of contaminants in the Background Study3.
Selecting the Contaminants of Potential Concern (COPCs)
The assessment of the indoor environment began with a review of historical information on
hazardous substances that have been associated with building fires and collapses [Wallace,
1990]. Many compounds, including combustion by-products such as dioxins and polycyclic
aromatic hydrocarbons (PAHs) were identified for further investigation, along with building
materials such as asbestos and fibrous glass. In addition, ambient air, indoor air, and
indoor/outdoor bulk dust monitoring data were reviewed. Data sources included EPA's ambient
air and bulk dust/debris monitoring program (www.epa gov/wtc), OSHA's air/dust monitoring
1 Agencies include the U S. Environmental Protection Agency (EPA), Agency for Toxics and Disease Registry
(ATSDR), New York State Department of Health (NYSDOH), New York City Department of Health (NYCDOH),
Occupational Safety and Health Administration (OSHA), New York State Department of Environmental
Conservation (NYSDEC) and New York City Department of Environmental Protection (NYCDEP)
2EPA is conducting a pilot program in an uncleaned/unoccupied building at 110 Liberty Street to determine the
effectiveness of various cleaning methods for removing asbestos and other contaminants of potential concern from
residential dwellings
'Most if not all of the pollutants associated with the collapse of the World Trade Center were present in New York
City's environment pnor to September 11 To establish a baseline for the presence of these contaminants in affected
residences, EPA will collect and analyze samples to look for some of these pollutants in apartments in parts of
Manhattan that were not impacted The Agency will use the data to determine pre-existing or "background" levels
of these pollutants in interior spaces in New York City
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data and the NYCDOH/ATSDR indoor air pilot program [NYCDOH, 2002], A concerted effort
also was made to identify and review additional sources of WTC-related data from other
governmental agencies (e g , U.S. Geological Survey, NYC Board of Education), academic
institutions, environmental organizations, and the private sector.
A semi-quantitative screening process was performed on the collected sampling data. Based on
frequency-of-detection, concentration and inherent toxicity, contaminants that exceeded health-
based screening levels for the ambient air (see Appendix B) were identified. Dioxin and PAHs
were added to the COPC list by this process. In addition, building constituents with carcinogenic
(asbestos) or irritant effects (fibrous glass, crystalline silica) that were consistently and
significantly found in bulk debris and mdoor dust samples were identified as COPCs
[NYCDOH, 2002]. Finally, lead (Pb) was included based on a comparison of sampling data with
existing regulatory standards. Collectively, the resulting group of contaminants are called
"contaminants of potential concern" or COPCs in this report
The list of COPCs is shown in the column at the left, below. Included for each COPC is a data
summary that supports its inclusion on the list For completeness, an additional list is included
on the right containing substances that, for various reasons, have created concern, but on closer
inspection, were either rarely detected in the ambient air and/or settled dust sampling around the
WTC, or routinely found at concentrations below the health-based screening criteria presented in
Appendix B.
Lead and Combustion By-Products (PAHs, Dioxin)
Lead. EPA's ambient air monitoring data detected lead in concentrations that exceeded 1.5
ug/m3 on five occasions from September 18-27, 2001. It should be noted that the National
Ambient Air Quality Standard (NAAQS) for lead is 1.5 ug/m3, but is based on a three-month
average. Since the ambient monitoring program began, no three-month average of the ambient air
data for lead exceeded the NAAQS of 1.5 ug/m3. However, lead was more commonly found at
concentrations that exceeded 0.1 ug/m3, the default value employed in EPA's Integrated
Exposure Uptake Biokmetic Model for Lead in Children [EPA, 1994]. This value represents the
upper-bound of average of ambient airborne lead concentrations in urban environments.
Additional support for including lead as a COPC was provided by a report that characterized the
dust that settled over lower Manhattan after the WTC collapse [Lioy, 2002]. The lead
COPCs
Other Substances
Lead
PAHs
Dioxin
Asbestos
Fibrous Glass
Crystalline Silica
Benzene
PCBs
Chromium
Cadmium
Manganese
Mercury
Particulate Matter
Refractory Ceramic Fibers
Mold
6
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concentration in settled dust ranged from 101 - 625 parts per million (ppm). By itself, this range
does not represent extraordinarily high concentrations, but in combination with the mass of
materia] released from the collapse of the towers, it represents a potentially significant increase in
the mass of lead deposited in lower Manhattan. Therefore, lead is included as a COPC
PAHs. Limited ambient air sampling was conducted for PAHs during the period of time
(September through December, 2001) when combustion processes were occurring at the site.
However, concentrations in bulk dust [EPA, 2002a and Lioy, 2002] exceeded the removal
guidelines for soil in EPA's Hazard Evaluation Handbook [EPA, 1997] of 9 ppm based on
benzo(a)pyrene equivalents. This value is risk-based, equating to an excess lifetime cancer risk of
lxlO"4 over a 30-year exposure duration for residential settings. Therefore, PAHs are included as
a COPC.
Dioxin. Ambient air samples exceeded EPA's screening criteria (see Appendix B) at various
sampling stations during September and October, 2001. Data trend analysis for dioxin in ambient
air [EPA, 2002a] showed that concentrations significantly exceeded the risk-based screening
level of 0.001 - 0.005 ng/m3. This range was based on an excess lifetime cancer risk of lxl 0"4
over a 30 year exposure duration for residential settings, using both the existing cancer Slope
Factor [Integrated Risk Information System (IRIS), 2002] and proposed cancer Slope Factor in
EPA's draft dioxin reassessment [EPA, 2001]. Therefore, dioxin (and related congeners) is
included as a COPC.
Building Materials (Asbestos, Fibrous Glass, Crystalline Silica)
The evaluation of building materials for inclusion as COPCs required a different approach than
that used for the combustion by-products. Those compounds (PAHs, dioxm) benefit from
consensus toxicity criteria (i.e., IRIS-established cancer Slope Factors) that allow for a
quantitative screening paradigm. With the exception of asbestos, the building materials
evaluated (including fibrous glass, crystalline silica, mica, portlandite, calcite and gypsum) do
not have IRIS inhalation toxicity criteria from which to perform quantitative risk assessments.
Complicating this matter is the knowledge that many of these substances were deposited in a
large cloud from the collapse of the towers. Thus, the settled dust may serve as a reservoir for re-
suspension and eventual inhalation exposure. In addition, materials such as fibrous glass can
also cause contact irritation when exposed directly to the skin.
The potential for exposure to building materials in the indoor environment was assessed by
reviewing sampling data on the constituent composition of the indoor/outdoor bulk dust and
indoor/ambient air [EPA, 2002c; USGS, 2001; NYCDOH, 2002, Chatfield & Kormnsky, 2001].
Toxicity criteria for building materials (with the exception of asbestos) were obtained from
occupational sources, such as the Occupational Safety and Health Administration's permissible
exposure limits (OSHA PELs), and the American Conference of Governmental Industrial
Hygienists threshold limit values (ACGIH TLVs). The evaluation of exposure potential coupled
with toxicity information identified three COPCs (asbestos, fibrous glass and crystalline silica).
7
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Asbestos. In the days immediately following the disaster, EPA analyzed the settled bulk
dust/debris for asbestos content. More than one third of the approximately 150 samples
registered an asbestos concentration greater than 1% [EPA 2002c], Since that time, EPA has
taken the position that WTC-related dust should be considered potentially asbestos-contaminated
and handled accordingly. Additionally, indoor settled dust samples collected from residential
buildings in November and December 2001 indicated that 18% of the indoor locations sampled
contained measurable levels of asbestos [NYCDOH, 2002]. Therefore, asbestos is included as a
COPC.
Fibrous Glass. Analysis of WTC bulk dust/debris has consistently identified fibrous glass to be
a major constituent of the material [Lioy 2002, USGS 2001]. In addition, an NYCDOH/ATSDR
study [NYCDOH, 2002] found fibrous glass in the interior settled dust in 41% of the locations
sampled at concentrations up to 35%. Air samples collected in areas with fibrous glass in settled
dust indicate no fiber levels of immediate concern Although fiber counts were found in four
areas with slightly greater than background (0.004-0.006 f/cc), subsequent re-analysis indicated
actual fibrous glass concentrations from these areas as 0.00004 to 0.00026 f/cc. Air samples
from remaining areas showed a maximum 0.003 f7cc total fiber count by PCM. These wools
may be skin, eye, and respiratory tract irritants. Although there are no standards to evaluate the
settled dust content, the presence of fibrous glass in settled dust does indicate a potential for
exposure Therefore, fibrous glass is included as a COPC.
Crystalline Silica. Settled dust and air samples taken in indoor and outdoor areas of residential
buildings in November and December of 2001 indicate the presence of alpha-quartz. Other
forms of crystalline silica were not found. This is consistent with outdoor dust and debris
samples collected by the USGS [IJSGS, 2001] and subjected to mineral analysis Quartz was
found in approximately 49% of the settled dust samples from indoor areas of residential
buildings and all of the associated outdoor areas sampled. Levels of quartz ranged as high as an
estimated 31.4% of the dust by weight in a residence. Since quartz is a common material in
sand, finding this mineral in a city where there is a great deal of concrete is not unusual.
However, quartz in dust from a comparison area unaffected by the WTC collapse ranged from
non-detect only up to an estimated 2.2% in the residence [NYCDOH, 2002], Seventeen
residential areas and eleven common areas had quartz levels greater than the associated
comparison area. Therefore, quartz was deemed to be elevated in some indoor areas of lower
Manhattan relative to the comparison area Additionally, quartz was found in 13% of the
respirable fraction air samples taken in these areas, ranging from an estimated 4-19 ug/m3,
demonstrating a potential for exposure. Although below occupational standards, this estimated
concentration is above the effective NAAQS standard for the silica fraction of respirable
particulate matter. Therefore crystalline silica, measured as alpha-quartz, is included as a COPC.
In addition to crystalline silica, calcite, portlandite and gypsum were the most abundant minerals
detected in settled dust samples from residential areas in lower Manhattan following the WTC
collapse. Mica was detected with much less frequency, generally at less than 0.1% of the dust.
Halite (salt) was also detected at trace levels. Calcite, portlandite, and gypsum are typical
components of concrete and gypsum based wallboard products, which were present in the WTC
buildings. While high concentrations of these minerals in airborne dust constitute a short-term
8
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health concern in the form of eye, nose and throat irritation, persisting adverse heath effects
would not be anticipated, unless these minerals remained suspended in high concentrations.
Indoor and street-level outdoor air sampling done in November and December of 2001 show that
the levels of these chemicals, over a time-weighted sample, were below levels associated with
irritant effects (See Table 1). Although there are methodological difficulties in quantifying these
materials by X-ray Diffraction (XRD) techniques, a semi-quantitative screening of the results
showed that the air levels were orders of magnitude below occupational standards for irritant
effects. However, since the presence of minerals in settled dust indicates there is potential for the
materials to be resuspended, these minerals should be evaluated qualitatively. Therefore,
although no screening levels are developed for these minerals as COPCs, the Pilot Cleaning
Effectiveness Initiative mentioned in the Introduction will report qualitatively on the presence of
gypsum, calcite and portlandite, while the quantitative analyses for crystalline silica (a COPC
discussed above) are being performed by XRD (following NIOSH Method 7500).
Table 1. Index of NIOSH and OSHA exposure limits and estimated maximum values in Lower
Manhattan.
Mineral
NIOSH REL
(ug/m3)
OSHA PEL (ug/m3)
*Maximum Estimated
Value (J) in Lower
Manhattan (ug/m3)
Gypsum
10,000 ug/m3 (total)
5,000 (ug/m3 resp)
15,000 ug/m3 (total)
5,000 (resp)
14J (PM100)
15J (PM4)
Portlandite
5,000 ug/m3
15,000 ug/m3 (total)
5,000 ug/m3 (resp)
95 J (PM100)
84J (PM4)
Calcite
10,000 ug/m3 (total)
5,000 ug/m3 (resp)
15,000 ug/m3 (total)
5,000 ug/m3 (resp)
14J (PM100)
10J (PM 4)
NIOSH = National Institute of Occupational Safety and Health, Centers for Disease
Control and Prevention
REL = recommended exposure level/limit
OSHA = Occupational Safety and Health Administration
PEL = permissible exposure limit,
resp = respirable
* fNYCDOH, 20021
Other Substances that Were not Selected to be COPCs
The following summary is provided for substances that were investigated, but not included on
the COPC list. A full discussion of the reasons is provided in Appendix A.
9
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Chemical
Reason
Benzene
Benzene is very volatile and dissipates into ambient air quickly. Grab samples
that recorded high (above the OSHA PEL of 1 ppm) concentrations on the
debris pile consistently dropped to below detection limits (20 ppb) at the site
perimeter.
PCBs
In over 500 ambient air samples taken around the WTC work zone, none
exceeded EPA's screening level of concern for ambient air (see Appendix B).
Chromium
All measurements (over 300 samples) of chromium in ambient air around the
WTC work zone have been below EPA's screening level of concern for the
ambient air (see Appendix B). Measurements in settled dust have been below
EPA Removal Action Guidelines [EPA, 1997].
Cadmium
Cadmium was found in only two out of 300 air samples at levels greater than
EPA's screening level for ambient air (Appendix B). Measurements m settled
dust have been below EPA Removal Action Guidelines [EPA, 1997].
Manganese
Manganese was found in only four of over 300 air samples at levels that were
greater than EPA's screening level for ambient air (Appendix B). Measurements
m settled dust have been below EPA Removal Action Guidelines [EPA, 1997]
Mercury
Concern regarding mercury has been raised by a report of slightly elevated
blood mercury levels in four Port Authority Police Officers at the WTC site (69
were screened). A NYC Department of Design and Construction report
[Rottner, 2002] concluded that air and bulk data have not shown elevated Hg
levels. The report also noted that routine urine screening of NYC firefighters
assigned to the site did not indicate any sign of Hg exposure. A U.S. Geological
Survey leachability study [USGS 2001] of indoor and outdoor WTC settled dust
samples showed that it is unlikely that harmful levels of mercury could ever be
released to the air. In addition, indoor air sampling using a Lumex Analyzer at
numerous residential dwellings close to Ground Zero determined mercury vapor
concentrations to be well below EPA's Reference Concentration (RfC) of
.3 ug/m3 [Johnson, 2002].
Particulate
Matter
(PM)
Ambient monitoring in the WTC area has shown that, since late October, levels
of PM 10 and PM 2.5 (two commonly measured inhalable PM sizes) have been
below EPA's level of concern for the ambient air (see Appendix B), indicating
that there is no continuing source of PM entering homes and offices. EPA's
Environmental Data Trend Report World Trade Center, 9/11/01 - 4/24/02 [EPA,
2002a] concluded that PM 2.5 and PM 10 appear to have returned to levels of a
steady background state.
10
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Chemical
Reason
Refractory
Ceramic
Fibers
(RCF)
Ceramic fiber-containing materials are not expected to be present in the WTC
buildings, as they are mainly used in industrial high temperature applications.
Limited sampling conducted by NYCDOH, 2002 did not indicate any ceramic
fibers in four indoor air samples analyzed by scanning electron microscopy
(SEM).
Mold
Mold was not directly associated with the WTC collapse. However, it may have
resulted from the combination of water damage and inoperable HVAC systems.
Guidelines for identifying and removing mold are provided through a NYCDOH
website (see Appendix A).
Setting Benchmarks for the Contaminants of Potential Concern (COPCs)
A tiered approach was used to evaluate the health risks posed by contaminants that might be
present in the indoor environment (air and settled dust). For each COPC, three levels were
established:
Tier I Level above which, after elimination of potential indoor sources (combustion
by-products, stored chemicals, etc.), aggressive clean-up action should be
taken expeditiously along with follow-up sampling to confirm attainment of
Tier III level
Tier II Range where diligent cleaning should continue, after elimination of potential
indoor sources (combustion by-products, stored chemicals, etc.), with follow-
up sampling to confirm attainment of Tier III level
Tier III Level below which the risk is negligible or consistent with the New York City
background level found in the aforementioned Background Study (see
Introduction).
The following hierarchal approach was employed for developing benchmark values: l)Use of
relevant and appropriate environmental standards/regulations; 2) Calculation of risk-based
benchmarks using EPA risk assessment guidance; and, 3) Adaptation of occupational standards
with additional safety factors. Accordingly, a review of environmental standards/regulations
was conducted for each of the six COPCs. As a result of this exercise Tier I screening levels for
lead in indoor air and settled dust were set using EPA's National Ambient Air Quality Standard
(NAAQS) and the U.S. Housing and Urban Development's (HUD's) standard for floors,
respectively. The clearance criteria established in the Asbestos Hazard Emergency Response Act
(AHERA, 1986) of 70 structures/mm2 was utilized to evaluate asbestos samples from the
ambient air monitoring effort. As detailed in Appendix B, the upper bound estimate for exposure
duration to contaminants in the ambient air was one year. However, given the potential for
extended exposure in residential dwellings, AHERA was deemed less appropriate to this setting
11
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In cases where appropriate standards did not exist (e.g , asbestos), risk-based criteria were
developed using established EPA risk assessment methods: for mdoor air, methods described in
EPA's "Risk Assessment Guidance for Superfund" [RAGS, 1989] were used; for settled dust,
EPA Region Ill's "Wipe Sample Assessment" guidance was utilized with modifications (see
Appendix D). The risk-based criteria reflect the most current toxicity criteria (Cancer Slope
Factors and RfDs/RfCs) on EPA's Integrated Risk Information System (IRIS), which is a
regularly updated (quarterly), online database that reports chemical toxicity reference values and
information on human health effects that may result from exposure to chemicals in the
environment
For contaminants that lacked IRIS verified toxicity criteria, occupational standards were
employed. Additional safety factors were added to account for higher exposure and greater
sensitivity within the general population.
The clearance criteria paradigm described above is pathway and chemical specific. Accordingly,
the benchmarks for each COPC do not account for multimedia and multiple chemical exposure.
Individual sampling results that exceed benchmark values should not be interpreted to represent
the occurrence of an adverse health effect. Because benchmark levels assume continuous
exposure for an extended duration, the average of the measured concentrations is more
appropriate for evaluating risk than individual measurements Consequently, isolated individual
values above the benchmark level may not necessarily be indicative of a hazard.
Developing Risk-Based Criteria for Indoor Air
For carcinogenic compounds, the benchmarks were set so that a local resident's lifetime risk of
developing cancer from exposure to WTC-related contaminants would not exceed a one-in-ten-
thousand probability (lxlO"4) above the resident's background risk without this exposure. The
amount of time that residents and office workers were exposed to WTC-related contaminants is
unknown. To be conservative, the Tier I screening level was chosen to be protective of a resident
who may have been exposed to WTC-related contaminants for one year. The Tier III clearance
level was chosen to be protective of a resident who is exposed to WTC-related contaminants for
30 years, which is the upper-bound estimate for residency in one dwelling [EPA, 1989]. Cancer
risk from less-than-lifetime inhalation exposure is given as.
Risk = LAC * UR
where LAC is the air concentration averaged over a lifetime, calculated as: AC * [EF*ED/LT],
where AC is the average air concentration during the period of exposure (ng/m3), EF is the
exposure frequency (days/year), ED is the exposure duration (years), LT is lifetime (days), and
UR is the unit risk factor, expressed in units of 1/concentration.
The following table lists the input parameters and numerical values (along with a brief
explanation) used in this procedure. (See Appendix D for equations and a more detailed
discussion).
12
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Table 2. Exposure parameters for calculating clearance criteria for air samples.
Input Parameter
Value
Explanation
Risk
1 x 10"*
See Appendix C
AT-(Averaging Time -
Carcinogens) of LT
25,550 days
See Appendix D
ED (Exposure Duration)
30 years
Upper-bound Estimate of Time in
Residence [EPA, 1989]
EF (Exposure Frequency)
365 days/yr
Days in Residence [EPA, 1989]
IUR (Inhalation Unit Risk)
2 3 E -01 (asbestos)
2.86 E +5 (dioxin)*
7.3 E 0 (PAHs)*
IRIS,2002
Dioxin Reassessment, EPA, 2001
IRIS,2002
*IUR was calculated by route-to-route extrapolation of oral Slope Factor
The cancer risk level (IxlO"4) employed herein reflects the upper bound of the acceptable risk
range (10"4 to 10"6) established in EPA's Superfund regulation [Federal Register, 1990]. Practical
Quantitation Limits (PQLs, the lowest level that can be reliably achieved within specified limits
of precision and accuracy during routine laboratory operating procedures [EPA, 1992]) and
anticipated background levels [ATSDR, 1995] dictated the selection of the nsk level at lxl 0"4 A
more detailed discussion of this subject can be found in Appendix C.
For non-carcinogenic compounds, airborne contaminant concentration is compared to the
Reference Concentration (RfC). The RfC is an estimate of a chronic exposure concentration for
the human population, including sensitive subpopulations, that is likely to be without an
appreciable risk of deleterious effects during a lifetime [EPA, 1989]. That comparison (i.e,
chronic exposure concentration (CEC) divided by the RfC) is called the Hazard Quotient (HQ).
HQ = CEC/RfC
where CEC is the daily averaged air concentration, calculated as: AC * [EF*ED/AT-NC], where
AC is the average air concentration during the period of exposure (ng/m3), EF is the exposure
frequency (days), ED is exposure duration (years), AT-NC is the averaging time for non-
carcinogens, and RfC is the reference concentration, expressed in units of 1/concentration.
According to EPA guidelines [EPA, 1989], if the HQ is greater than one, there may be concern
for potential health effects. Therefore, for Tier III (clearance level), the benchmark screening
level was set at an HQ of 1. For Tier I, which equates to a sub-chronic exposure scenario, an HQ
of 10 was used, in accordance with EPA's Hazard Evaluation Handbook [EPA, 1997]. An HQ of
10 accounts for the fact that chronic toxicity criteria (RfDs/RfCs) are being applied to
sub-chronic exposure scenarios (i.e., exposure not expected to exceed 6 months to one year in
duration) Accordingly, an HQ of 10 was used for non-carcinogens to reflect a similar (i.e.,
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upper bound of 1 year) exposure duration. Note that contaminants (both non-carcinogens and
carcinogens, alike) can exhibit acute effects from short-term, high-dose exposures. Because the
Tier I benchmark levels are based on subchronic exposure (i.e., 1 year), acute effects from
exposures that are below the benchmark levels would be unlikely. A review of EPA's draft
Acute Exposure Guideline Levels [EPA, 2001 a] and California EPA's (CAL-EPA) Acute Risk
Levels demonstrates that the benchmark levels developed herein are categorically more stringent
than the analogous US EPA and Cal-EPA acute levels.
Developing Risk-Based Criteria for Settled Dust
There is no established national guidance, and limited scientific literature, for assessing risk from
interior surface wipe sampling (i.e., mass per unit area) data . The approach used in this report
was adapted and modified from a methodology developed by the EPA Region III Superfund
Program It has been employed by the U S. Army Corps of Engineers to develop risk-based
clean-up goals for intenor surfaces at the Claremont Polychemical Superfund site in Region II
[Radian, 1999] Additionally, the methodology is similar to an approach employed by the
NYSDOH for evaluating a dioxin contaminated office building [NYSDOH, 1985] and one
previously proposed by NJDEP for setting interior building surface clean-up goals [NJDEP,
1993],
A full discussion of the methodology employed for developing risk-based benchmarks based on
contact with residues on indoor surfaces is presented in Appendix D. Briefly, this methodology
provides an estimate of daily dose resulting from dermal absorption and ingestion associated
with contacting contaminated surfaces and hand-to-mouth transfers Dose is obtained by
estimating the following: skin contact area and contact frequency with contaminated surfaces,
transfer efficiency between surface and hand, transfer efficiency between hand and mouth, oral
absorption of the contaminant and dermal absorption of residual contamination on skin.
Consistent with the approach for indoor air, toxicity criteria were obtained from IRIS. The
assessment procedure is described briefly below and in more detail in Appendix D.
For the purpose of developing risk-based clearance levels for intenor surfaces, this approach is
preferable to an approach that relies on measuring contaminant concentration on a mass per mass
(ppm) basis (as might be done for an extenor soil assessment). After cleaning has occurred, it
would be difficult to obtain the mass of dust necessary to perform a mass per mass measurement
of contaminant concentration. In addition, literature on intenor lead contamination demonstrates
a strong correlation between lead load (mass per unit area) and blood lead concentration in
children (Lanphear et. al., 1998).
The following table lists the input parameters and numerical values (along with a brief
explanation) used in this procedure (See Appendix D for equations and a more detailed
discussion.)
Table 3. Exposure parameters used to calculate clearance cntena for wipe samples.
14
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Input Parameter
Value
Explanation
SA (Skin Surface Area)
400 cm2
Palm Side of Hands
CF (Contact Frequency)
16/day
See Appendix D
FTSS (Fraction Transferred from
Surface to Skin)
0.05
See Appendix D
EF (Exposure Frequency)
365 days/yr
Days in Residence [EPA, 1989]
ED (Exposure Duration)
30 years
Upper-bound Estimate of Time in
Residence [EPA, 1989]
ABSo (Oral Absorption Fraction)
1
See Appendix D
FTSM (Fraction Transferred from
Skin to Mouth)
0.1
See Appendix D
ABSd (Dermal Absorption Fraction)
0.03 (dioxin)
0.13 (PAHs)
Chemical Specific [EPA, 2001b]
BW (Body Weight)
70 kg
Average Adult [EPA, 1989]
AT-NC (Averaging Time - Non
Carcinogen)
-

AT-C (Averaging Time -
Carcinogen)
25,550 days
See Appendix D
CSF (Cancer slope factor -dermal
and oral)
1.0 E+6 (dioxin)
7 3 E 0 (PAHs)
Dioxin Reassessment: EPA, 2001
IRIS,2002
In light of the limited data for many of the input parameters used to estimate dose from exposure
to residues on surfaces, conservative exposure estimates were employed. Still, there may be a
concern for highly exposed sub-populations. Infants and young children constitute such a group
due to age-specific activities such as crawling and mouthing and increased surface-area to body-
weight ratios. In cases where non-carcinogenic effects are driving clearance levels, the
difference in dose on a mg/kg/day basis between an adult and a young child could be
considerable. However, in this document the two compounds (dioxin, PAHs) for which the
surface contact methodology has been used to develop clearance levels are carcinogens, so it is
this effect that drives the clearance levels. As such, the Tier III clearance level is strongly
influenced by overall exposure duration, which in this assessment has been set at 30 years.
Consequently, weighted over 30 years, the impact of a high-exposure period (i.e., early
childhood) is diluted It is acknowledged that Tier I (one year exposure duration) screemng
levels for carcinogens may underestimate cancer risk for children, but Tier I contaminant levels
are not expected to persist, therefore the magnitude of any associated uncertainty would be small.
If a contaminant was to be added to the COPC list that had its clearance level based on a non-
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carcinogenic endpoint, a separate wipe assessment analysis should be performed taking into
account childhood exposure parameters. A more complete discussion of the uncertainties
associated with the methodology for surface contact assessment is presented in Appendix D.
With the exception of asbestos, the extremely limited air sampling data for specific building
constituents in indoor air dictated that an assessment approach had to be based on historical data
relating the concentration of fibers in air (fibers per cubic centimeters or f7cc) to the load in
settled dust (fibers per square centimeters or f7cm2) [Millette and Hays 1994]. Although the
empirical relationships (called K factors) are not rigorous enough to rely on for a firm health
decision, they are used in this report to define what might constitute elevated building material
counts that would need to be addressed on a near-term basis. This approach may overestimate
potential exposures but, as such, is protective
Developing Benchmark Levels Based on Occupational Health Standards
For fibrous glass and silica, nsk-based methods were not available for indoor air due to lack of
established environmental toxicity criteria. Therefore, benchmark levels were set based on
occupational health standards established by the American Conference of Governmental
Industrial Hygienists [ACGIH] (called "threshold limit values" or TLVs) and the Occupational
Safety and Health Administration [OSHA] (called "permissible exposure limits" or PELs).
TLVs/PELs are established to protect employees who might have been exposed to substances
during an eight-hour day, for five days a week. For Tier I levels, TLVs/PELs were divided by
ten to be more protective of residents who might be exposed to substances twenty-four hours a
day, seven days a week. In addition, the TLVs/PELs were established to protect a healthy
worker. For Tier III levels, TLVs or PELs were divided by 100 to be protective of a more
diverse population that includes sensitive individuals such as children, older adults, and the
infirm.
The following tables show the benchmark levels developed for each contaminant of potential
concern. Each table is accompanied by risk equations, toxicity criteria and a summary of any
contaminant-specific assumptions that were made in developing the benchmark values.
16
-------
Table 4. Lead
Tier
Action
Lead (settled dust)
Lead (indoor air)

Level
Basis
Level
Basis
I
Aggressive
cleaning If levels
persist, take
additional action to
reduce exposure.
>40 ug/fit2
1) HUD standard
for floors
2) Residential
Lead Hazard
Standard (TSCA
Section 403)
>1 5 ug/m3
NAAQS
(intended to
keep 99 5% of
children below
30 ug/dl)
II
Maintain
recommended
cleaning methods
Consider additional
monitoring
40 ug/ft2 to 25
ug/ft (or
background)
25 ug/ft2 is HUD
screening level
for floors
1.5 ug/m3 to
1 ug/m3 (or
background)
1 ug/m3 is the
calculated value
using EPA's
IEUBK Lead
Model for
Children*
III
No further action
<25 ug/ft2 (or
background)
Level could also
be set at that
found in
background, or
unaffected, areas,
so that no
increase in risk
due to lead
would be
expected
1 ug/m3 (or
background)
Level could also
be set at that
found in
background, or
unaffected,
areas, so that no
increase in risk
due to lead
would be
expected.
* EPA developed the Integrated Exposure Uptake Biokinetic (IEUBK) Lead Model [EPA, 1994]
to evaluate multimedia lead exposure to children in residential settings. EPA established a goal
of attaining a 95% probability that blood lead levels in children be less than 10 ug/dl [EPA
1994a]. Setting the indoor air lead concentration at 1 ug/m3 (and using background
concentrations for lead in water, diet, soil and dust) the IEUBK Lead Model estimates that 96%
of the blood lead probability distribution falls below 10 ug/dl See Appendix E for model run
data files and graph of blood lead probability distribution
17
-------
Table 5. Polvcvchc Aromatic Hydrocarbons (PAHsl
Tier
Action
PAHs (settled dust)
PAHs (indoor air)

Level
Basis
Level
Basis
I
Aggressive
cleaning If levels
persist, take
additional action to
reduce exposure
>9 mg/m2
9 mg/m2
represents a
lxlO"4 risk
estimate for a 1
year exposure
>6 ug/m3
6 ug/m3
represents a
lxlO"4 risk
estimate for a 1
year exposure
II
Maintain
recommended
cleaning methods.
Consider
additional
monitoring
9 mg/m2 to 0.3
mg/m2 (or
background)
0 3 mg/m2
represents a
lxlO"4 risk
estimate for a
30 year
exposure
6 ug/m3 to 0 2
ug/m3 (or
background)
0 2 ug/m3
represents a
lxlO"4 risk
estimate for a
30 year
exposure
III
No further action
<0 3 mg/m2 (or
background)
Level could also
be set at that
found in
background, or
unaffected,
areas, so that no
increase in risk
due to PAHs
would be
expected.
<0.2 ug/m3 (or
background)
Level could
also be set at
that found in
background, or
unaffected,
areas, so that
no increase in
risk due to
PAHs would
be expected
Toxicity criteria for benzo{a)pyrene:
Oral Slope Factor = 7.3 E 00 (mg/kg/day)"' (IRIS, 2002)
(Inhalation cancer risk was calculated by route-to- route extrapolation of oral Slope Factor)
The following carcinogenic PAHs are evaluated as benzo(a)pyrene-equivalents [EPA, 1993]:
Compound Relative Potency
Benzo(a)pyrene
1
Benz(a)anthracene
0.1
Benzo(b)fl uoran thene
0.1
Benzo(k)fluoranthene
001
Chrysene
0.001
Dibenzo(a,h)anthracene
1
Indeno(l ,2,3-c,d)pyrene
0.1
18
-------
Table 6. Dioxin
Tier
Action
Dioxin (settled dust)
Dioxin (indoor air)

Level
Basis
Level
Basis
I
Aggressive
cleaning. If levels
persist, take
additional action to
reduce exposure.
>120 ng/m2
120 ng/m2
represents a
lxl 0"4 risk
estimate for a 1
year exposure
>0 03 ng/m3
0.03 ng/m3
represents a
lxl 0"4 risk
estimate for a 1
year exposure
II
Maintain
recommended
cleaning methods
Consider additional
monitoring
120 ng/m2 to
4 ng/m2 (or
background)
4 ng/m2
represents a
lxlO"4 risk
estimate for a 30
year exposure
0.03 ng/m3 to
0 001 ng/m3 (or
background)
0 001 ng/m3
represents a
1 x 10"4 risk
estimate for a
30 year
exposure
III
No further action
<4 ng/m2 (or
background)
Level could also
be set at that
found in
background, or
unaffected, areas,
so that no
increase in risk
due to dioxin
would be
expected
<0.001 ng/m3
(or background)
Level could
also be set at
that found in
background, or
unaffected,
areas, so that
no increase in
risk due to
dioxin would
be expected
Toxicity criteria for dioxin:
Oral Slope Factor = 1.0 E 06 (mg/kg/day)"1 [EPA, 2001]
(Inhalation cancer risk was calculated by route-to- route extrapolation of oral Slope Factor)
The table above reflects the proposed cancer Slope Factor for 2,3,7,8 TCDD and the toxicity
equivalence (TEQ) paradigm for carcinogenic dioxin/fiiran congeners present in EPA's draft
dioxin reassessment [EPA, 2001]. An equivalent table reflecting the previous ERIS-verified
cancer Slope Factor for 2,3,7,8 TCDD would be represented by multiplying all listed values by a
factor of six.
The methodology for estimating dose from wipe sampling data (see Appendix D) is consistent
with the approach NYSDOH used in assessing office buildings in Binghamton, with
modifications made to input parameters to reflect residential rather than occupational exposure.
In addition, the Tier III benchmark equates to a lifetime exposure level which is approximately
one tenth of that which results from current dietary intake of dioxin (65 pg/d). It is thus
19
-------
reasonable to assume that any lower level of exposure would result in an inconsequential
reduction in the current risk levels experienced by the general U.S. population.
Information regarding NYC background levels also would be an important consideration in
determining the appropriate longer-term value. This report proposes selecting the longer-term
value on the basis of a lxlO"4 risk level or NYC background, as determined by the WTC-directed
Background Study
20
-------
Table 7. Asbestos
Tier
Action
Asbestos (Settled Dust)
Asbestos (indoor air)

Level
Basis
Level
Basis
I
Aggressive
> 30,000
Millette's K
>0.028 f/cc
0 028 f/cc

cleaning. If levels
f7cm2
factor to estimate
(PCME*)
represents a lxlO*4

persist, take

airborne levels for

risk estimate for a

additional action to

different activities

1 year exposure

reduce exposure.

(see narrative

below)

Evaluate

conditions m the

area, including

representativeness

of air samples,

asbestos settled

dust levels, and

11
Maintain
30,000

0.028 f/cc
0.0009 f/cc

recommended
ftcm2 to

0 0009 f/cc
represents a lxl0^

cleaning methods.
background

(or
risk estimate for a

Consider

background)
30 year exposure

additional

monitoring.

Evaluate

conditions in the

area including

representativeness

of air samples,

fibrous glass

settled dust levels

and loading

III
No further action
Background
Level is set at that
0 0009 f/cc
Level is set at that

required.

found in
(PCME*)
found in

background, or
(or
background, or

unaffected, areas,
background)
unaffected, areas

so that no increase

In this way, no

in risk due to the

increase in risk due

asbestos fibers

to the asbestos

would be

fibers would be

expected

expected
PCME - fibers greater than 5 micrometers long (aspect ratio >3:1). Analysis by
EM
21
-------
Toxicity criteria for asbestos:
Inhalation Unit Risk = 2.3 E-01 (f7cc)"' [IRIS, 2002]
Risk-based criteria were used to develop the Tiered benchmark levels for asbestos in air.
Conservative assumptions of continuous exposure to a constant level of airborne fibers for either
1 year (Tier I) or 30 years (Tier III) were combined with the IRIS Slope Factor to establish
benchmarks representative of a lx 10-4 estimate of excess lifetime cancer nsk for each scenario
This approach makes several assumptions, chief among those is the quantification of asbestos
fibers in air based on the PCM definition of a fiber (greater than Sum in length with an aspect
ratio of 3-l or greater) and the use of the IRIS Slope Factor which was designed to apply to fibers
so defined. Although there is some concern regarding shorter fibers, the approach used here
represents the current consensus by the US EPA for quantifying nsk of airborne asbestos fibers.
It should be noted there is ongoing debate regarding the nature of health effects which may be
attributed to shorter asbestos fibers Both EPA and ATSDR are currently pursuing meetings to
discuss and further refine these issues. However for the purposes of this response, addressing
PCM equivalent fibers is considered protective.
The Tier I level for asbestos in settled dust was based on K factors [Millette and Hays, 1994],
which are empirical relationships between concentrations of asbestos fibers in settled dust and
indoor air Millette developed the K factors by studying matched air and settled dust samples
taken from various homes, at varying levels of activity in the home. The Tier I level was based
on the K factor for a worst case scenario of a high level of activity. Although K factors are not
rigorous enough to rely upon for a firm health decision, they are used here only to define what
might constitute elevated fiber counts, that would need to be addressed as a near-term concern
This approach may overestimate potential exposures, but as such, is protective.
It should be noted that the airborne Tier I level of 0.028 f/cc PCM equivalents roughly equates to
the AHERA TEM standard of 70 f/mm2 (0.022 f/cc) in total fiber counts. Based on empirical
information from the WTC ambient air monitoring program [EPA, 2002c] that recorded less than
20% of total AHERA TEM fiber counts to be >5 um in length, the AHERA TEM standard of 70
f7mm2 (0.022 fee) and the alternate AHERA PCM standard of 0.01 f/cc both meet the risk-
based criteria established for the Tier I screening level.
22
-------
Table 8 Fibrous Glass
Tier
Action
Fibrous Glass (settled dust)
Fibrous Glass (indoor air)

Level
Basis
Level
Basis
I
Aggressive cleaning
If levels persist, take
additional action to
reduce exposure
Evaluate conditions in
the area including
representativeness of
air samples, fibrous
glass settled dust
levels and loading
> 100,000
f7cm2
Millette's K
factor to estimate
airborne levels for
different activities
(see narrative
below)
> 0.1 flee
ACGIH TLV of
1 f/cc (see
narrative below)
II
Maintain
recommended
cleaning methods.
Consider additional
monitoring
Evaluate conditions in
the area including
representativeness of
air samples, fibrous
glass settled dust
levels and loading.
100,000
f/cm2 to
background

0 01 to 0.1
f/cc

III
No further action
required
background
Level is set at that
found in
background, or
unaffected, areas
In this way, no
increase in risk
due to the fibers
would be
expected
< 0 01 f/cc
ACGIH TLV of
1 f/cc (see
narrative below)
* Fibers with length > 5|im with an aspect ratio > 3-1, as defined in the ACGIH TLV
Air concentrations measured by PCM, NIOSH 7400, confirmed by SEM.
The benchmarks for airborne fibrous glass were set based on the consideration that low level
exposures to fibrous glass would not pose the potential for significant long-term health effects
given the expected low biopersistence of these materials [ATSDR, 2002]. The current
occupational exposure standards for fibrous glass (glass and mineral wools) is established to
prevent the upper respiratory tract and skin irritant effects. In order to apply this standard to a
general population and accounting for a longer daily exposure than seen in the occupation
23
-------
setting, uncertainty factors were used to reduce the allowable airborne levels for the Tiered bench
marks. The Tier I benchmark is set at one tenth of the TLV and the Tier III level is set at 1
hundredth of the TLV. It is believed these levels will prevent conditions which may cause
irritant health effects for most individual.
Although fibrous glass in settled dust is known to be a contact irritant, little data exist to provide
a threshold relating to what fiber loading may result in skin irritation, or airborne levels of
concern However, as with asbestos it was deemed preferable to have a Tier I benchmark
available so that there was some upper bound to settled dust loadings that may trigger action.
Here again Millet's K factors were used to correlate dust loading levels to the air benchmarks.
The Tier I level for fibrous glass in settled dust was based on Millette's K factors, which are
empirical relationships between concentrations of asbestos fibers in settled dust and indoor air.
Millette developed the K factors by studying matched air and settled dust samples taken from
various homes, at varying levels of activity in the home. The Tier I level was based on the K
factor for a worst case scenario of a high level of activity. Although K factors are based on
activity data for asbestos, they are believed to be protective for fibrous glass, which is larger and
less airborne. In addition, although K factors are not rigorous enough to rely upon for a firm
health decision, they are used here only to define what might constitute elevated fiber counts,
that would need to be addressed as a near-term concern. This approach may overestimate
potential exposures, but as such, is protective.
The Tier I level for fibrous glass in indoor air was based on the American Conference of
Governmental Industrial Hygienists' (ACGIH) threshold limit value (TLV) of 1 f7cc. That TLV
is based on limiting irritant effects of fibrous glass on workers The TLV was divided by a factor
of ten to account for the different exposure durations between ACGIH's workers and the WTC
area's residents
The Tier III level for fibrous glass in indoor air was based on the ACGIH TLV of 1 f/cc, divided
by a factor of 100 to account for greater exposure and the different sensitivities between
ACGIH's healthy works and the WTC area's more varied population
24
-------
Table 9 Crystalline silica - respirable fraction of alpha-quartz
Tier
Action
Crystalline Silica (settled
dust)
Crystalline Silica (indoor air)

Level
Basis
Level
Basis
I
Aggressive cleaning If
levels persist, take
additional action to
reduce exposure.
Evaluate conditions in
the area including
representativeness of
air samples, asbestos
settled dust levels and
loading

10 0 ng/m3
*
OSHA PEL of
100 pg/m3 (see
narrative
below)
II
Maintain recommended
cleaning methods.
Consider additional
monitoring.
Evaluate conditions m
the area including
representativeness of
air samples, fibrous
glass settled dust levels
and loading.
above
background

10.0 ng/m3
to 1 ng/m3
(or
background)
*

III
No further action
required.
background
Level is set at
that found in
background, or
unaffected, areas
In this way, no
increase in risk
due to the silica
in settled dust
would be
expected
1 pg/m3 or
background
OSHA PEL of
100 pg/m3 (see
narrative
below)
* Silica measured in airborne respirable dust, by NIOSH 7500.
The benchmarks for silica in indoor air were derived from the Occupational Safety and Health
Administration's (OSHA) permissible exposure limit (PEL) for dust containing 100% respirable
silica in air of 100 pg/m3 (0.1mg/m3)as a time weighted average for an 8 hour exposure.
Silica exposure poses risk of both cancer and non-cancer respiratory health effects. Although no
25
-------
Reference Concentration (RfC) or IRIS Slope Factor exists, there are methodologies for
examining risks of non-occupational exposures, on which to draw upon for a risk based approach
to set benchmark levels. The approach taken here is a dual approach, where in the face of
uncertainties the quantification of the benchmarks was based on the current occupational
standards. Broader risk-based discussion of other methodologies provides support for the chosen
benchmark levels although not quantitatively employed here to derive the benchmarks.
The Tier I benchmark is set at one tenth of the OSHA PEL. A single year of exposure at this
benchmark (10ug/m3) would provide a cumulative silica loading to the lungs less than the
lmg/m3 work-year loading which is believed to be the departure point for adverse health effects
Additionally this level is also the effective National Ambient Air Quality Standard for silica,
where PM10 at 50 ug/m3 contains no more than 10% crystalline silica. A recent review by
supports the finding that this level would be protective of long-term non-cancer health effects
[EPA, 1996]. The Tier III benchmark is set at one hundredth of the OSHA PEL. A 30 year
continuous exposure at this level would not result in a cumulative silica loading to the lungs
greater than the lmg/m3 year loading which is believed to be the departure point for adverse
health effects.
26
-------
References
Agency for Toxic Substances and Disease Registry. 1995. Toxicological Profile for Asbestos.
U.S. Dept. of Health and Human Services, Atlanta, GA
http://www atsdr.cdc.gov/toxprofltes/tp61 .html
Agency for Toxic Substances and Disease Registry. 2002. Technical Briefing
Paper' Health Effects from Exposure to Fibrous Glass, Rock Wool or Slag
Wool. Agency for Toxic Substances and Disease Registry, U.S. Department of
Health and Human Services, Atlanta, GA.
http://www.atsdrcdc.gov/DT/fibrous glass 061402.odf
Chatfield EJ, Kominsky JR. 2001 Characterization of Particulate Found m Apartments After
Destruction of the World Trade Center. Summary Report Prepared for Ground Zero Elected
Officials Task Force, New York.
bttt>://www eqm.com
Federal Register 3/8/90, EPA - National Contingency Plan 40 CFR Part 300,
hrtp v'Avww. epa. gov/superfund/comacts/newrriisc htm
Internationa] Agency for Research on Cancer (IARC). 1988. Monograph on Man-made Mineral
Fibers, Vol 43, p. 39. In: IARC Monographs of the Evaluation of Carcinogenic Risks to Humans.
International Agency for Research on Cancer, World Health Organization, Lyon, France
http://www.iarc.fr/
Integrated Risk Information System (IRIS) 2002 USEPA, Office of Research and Development.
Available on Ime at:
http.//www epa.gov/iris
Johnson C. 2002. Mercury Vapor Levels in Dwellings in Close Proximity to the WTC Site. City
University of New York.
Electronic link not available
Lanphear B.P., Matte T.D., Rogers J , et al. 1998. The Contribution of Lead-Contaminated
House Dust and Residential Soil to Children's Blood Lead Levels. Environ Res: (79) 51-68
http ://www.idealibrarv.com/links/doi/10.1006/enrs. 1998.3859
Lioy, P., et al. 2002. Characterization of the Dust/Smoke Aerosol that Settled East of the World
Trade Center (WTC) in Lower Manhattan after the Collapse of the WTC September 11, 2001.
EHP, Vol 110 (7) P. 703 -714.
http://157.98 13.103/m emb ers/2002/11 Qq 7 03-714110 v/li o v-fu 11 .html
Millette J.R., Hays S.M 1994 Settled Asbestos Dust Sampling and Analysis. CRC Press Boca
Raton, FL.
Electronic link not available
27
-------
New Jersey Department of Environmental Protection. 1993. Technical Basis and Background
for Cleanup Standards for Contaminated Sites. N.J.A.C. 7:26D (Draft).
New York City Department of Health and Agency for Toxic Substances and Disease Registry
2002. Final Technical Report of the Public Health Investigation to Assess Potential Exposures to
Airborne and Settled Surface Dust in Residential Areas of Lower Manhattan. Atlanta: US
Department of Health and Human Services.
Electronic link not available
New York State Department of Health 1985 PCB Re-Entry Guidelines. New York State
Department of Health, Bureau of Toxic Substances Assessment, Division of Environmental
Health Assessment Albany, NY. July 17. Document 1330P.
Electronic link not available
Radian International. 1999. Development of Risk-Based Wipe Sample Cleanup Levels at the
Claremont Polychemical Superfund Site in Old Bethpage, New York. Prepared for: U.S. Army
Corps of Engineers.
Electronic link not available
Rottner, B R. 2002. Special Technical Report: Occupational and Environmental Exposures to
Mercury at the World Trade Center Emergency Project. New York City Department of Design
and Construction.
Electronic link not available
U.S Department of Health and Human Services. 2001 Public Health Service National
Toxicology Program, 9th Report on Carcinogens, Revised January.
httpV/157.98.13.104/roc/toc9 html
U.S. Environmental Protection Agency (EPA). 1989 Risk Assessment Guidance for Superfund,
Volume 1: Human Health Evaluation Manual (Part A). OSWER, EPA/540/1-89/002.
http://www.epa.eov/superfund/programs/risk/ragsa/index.htm
U.S. Environmental Protection Agency (EPA). 1992. Guidance for Data Usability in Risk
Assessment (Part A). OSWER. 9285.7-09A.
http://www epa.gov/superfiind/Drograms/risk/datause/parta htm
U.S Environmental Protection Agency (EPA). 1993. Provisional Guidance for Quantitative
Risk Assessment of Polycyclic Aromatic Hydrocarbons. Office of Research and Development.
EPA/600/R-93/089.
http://www.epa.gov/cgi-bin/claritgw l7op-Displav&document=clservepa-cinn:4308:&rank=4&te
mplate=epa
U.S. Environmental Protection Agency (EPA). 1994. Guidance Manual for the Integrated
Exposure Uptake Biokinetic Model for Lead in Children.
28
-------
http://www.epa.gov/superfund/proerams/lead/ieubk htm
U S Environmental Protection Agency (EPA). 1994a. Revised Interim Soil Lead Guidance for
CERCLA Sites and RCRA Corrective Action Facilities. OSWER 9355.4-12
http://www.epa gov/superfund/programs/lead/
U.S. Environmental Protection Agency (EPA). 1996. Ambient Levels and Noncancer Health
Effects of Inhaled Crystalline and Amorphous Silica- Health Issue Assessment. EPA/600/R-
95/115.
http //www.epa.gov/ncea/pdfs/0604 pdf
U.S. Environmental Protection Agency (EPA), Region III. 1997 Hazard Evaluation Handbook
A Guide to Removal Actions. EPA 903/B-97-006.
Electronic link not available
U.S. Environmental Protection Agency (EPA) 2001. Exposure and Human Health Re-
assessment of 2,3,7.8- Tetrachlorodibenzo-p-dioxin (TCDD) and Related Compounds. Office of
Research and Development. Peer Review Draft.
httP'//cfbubl.epa.gov/ncea/cfrn/dioxreass.cfm?ActTvpe-default
U.S Environmental Protection Agency (EPA). 2001a. Acute Exposure Guideline Levels (Peer
Review Draft) OPPTS, Wash. D.C.
Electronic link not available
U.S. Environmental Protection Agency (EPA). 2001b. Risk Assessment Guidance for
Superfund Volume T Human Health Evaluation Manual (Part E, Supplemental Guidance for
Dermal Risk Assessment) Interim EPA/540/R/99/005. Review Draft.
http://www.epa gov/superfund/programs/risk/ragse/index htm
U.S. Environmental Protection Agency (EPA). 2002a. Special Investigative Audit #14:
Environmental Data Trend Report, World Trade Center Disaster; Final Update - Trends for Data
Collected 9/11/01 to 4/24/02 from Lower Manhattan. Prepared by IT Corporation for Office of
Emergency and Remedial Response.
http://www.nvcosh.org/WTCdraft2 102901 .pdf - (Draft Version - October 2001)
U.S. Environmental Protection Agency (EPA). 2002b Toxicological effects of fine particulate
matter derived from the destruction of the World Trade Center, April 2002 draft National
Health and Environmental Effects Research Laboratory, Office of Research and Development.
http://www epa gov/ORD/scienceforum/air abstracts/gavett pdf
U.S. Environmental Protection Agency (EPA). 2002c EPA Website for World Trade Center
Sampling Results.
http:// www. epa. go v/ wtc
U.S. Geological Survey (2001) Environmental Studies of the World Trade Center after the
29
-------
September 11, 2001 Attack. Open File Report OFR-010429.
http://greenwood cr uses.gov/Dub/open-file-reports/ofr-01-0429/
Wallace, Deborah. 1990. In the Mouth of the Dragon: Toxic Fires in the Age of Plastics Avery
Publishing Group, Inc., New York
Electronic link not available
30
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APPENDIX A
Hazardous Substances Not Included in Indoor Environment Sampling Program
Benzene
Benzene is a volatile organic chemical (VOC) that was found in emissions from the open flames
and smoldering debris left after the collapse of the WTC The benzene may have originated from
the airplanes' residual jet fuel or from the continuous burning of plastics and other materials
contained within the collapsed towers
Since the fires and smoldering debris persisted long after the collapse of the WTC towers, there
is a possibility that harmful levels of benzene vapor could have accumulated m nearby indoor
environments. However, because benzene is very volatile and dissipates into ambient air
quickly, the vapor plumes would have had to contain high concentrations of benzene, and the
indoor area would have had to be relatively close to the fire source in order for indoor amounts of
benzene to build up to harmful levels. In addition, unlike dioxin, benzene cannot become
adsorbed by dust particles and transported indoors to settle as a long-term potential hazard. Once
the source of the benzene is extinguished completely from the area, then benzene will dissipate
and will not be a hazard.
Results of samples taken within the immediate WTC work zone from September 11 through mid-
January 2002, show benzene levels of up to 180,000 parts per billion (ppb). However, tests
during the same time period outside the work zone show levels of benzene that were below the
established EPA screening level of 20 ppb for the ambient air (see Appendix B), indicating how
quickly benzene dissipates in the air A specific example, for the day of October 3, is shown
below:
From debris pile at From debris pile at From Liberty &
WTC North Tower WTC South Tower Greenwich Streets
28,000-39,000 ppb 4,300 ppb less than 20 ppb
From January 26 through April 23, 2002 (the most recent test date available) levels of benzene in
ambient air have remained below the 20 ppb screening level, except for one grab sample from the
immediate work zone on February 9 and another sample from the same location on February 12.
These tests indicate that the source of harmful ambient benzene levels has been extinguished, and
therefore there is no source of benzene available to accumulate in any indoor environment
Benzene will not be monitored in any further indoor environment testing.
Polvchlonnated Biphenvls TPCBs't
PCBs were historically used as coolants and lubricants in transformers, capacitors, and other
electrical equipment. It is possible that, with the WTC collapse, PCBs could have been dispersed
into the ambient air and then transported indoors. However, in well over 500 ambient air
samples taken around the WTC site, no measurements were found above EPA's screening level
of 730 ng/m3 in the ambient air (see Appendix B). This indicates that PCBs in ambient air are
not considered to be at harmful levels, therefore, PCBs will not be monitored in indoor
environment testing.
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Chromium
Chromium is a naturally occurring element commonly used in metal alloys and plumbing
coatings in high rise buildings such as the WTC. Chromium and its compounds can be found in
air as very fine dust particles that eventually settle over land, and can cause cancer and other
health problems if inhaled at high concentrations. To date, in over 300 air samples, levels of
chromium measured in ambient air around the WTC work zone have all been below EPA's
screening level of 0.6 ug/m3 in the ambient air (see Appendix B). Measurements in settled dust
[EPA 2002c, Lioy 2002] have been below EPA Removal Action Guidelines [EPA, 1997],
Because of these low values, chromium is not being considered a hazard at the WTC site
Therefore, chromium will not be monitored in any indoor environment testing.
Cadmium and Manganese
Cadmium and manganese, both hazardous air pollutants, were detected in some ambient air
samples taken at the WTC site. However, m over 300 samples, cadmium was found m only two
samples at levels over EPA's screening level of 0.2 ug/m3 in the ambient air (see Appendix B). In
over 300 samples, manganese was found in only four samples at levels above EPA's screening
value of 0.5 ug/m3 in the ambient air (see Appendix B) Because of the low ambient
concentrations of these two metals, they will not be monitored in any indoor environment testing
Mercury
In late December 2001, it was reported that four New York City Port Authority police officers
were tested with elevated levels of mercury in their blood This raised concerns over the air
quality at the WTC area. The officers were retested under medical surveillance to determine
whether the source of mercury was the air over the WTC. The retesting found that the levels of
mercury in the officers' blood and urine were below levels of concern established by NYCDOH
and the American Conference of Governmental Industrial Hygienists The cause of the first
elevated mercury levels is not known, but may be from something that the officers had eaten the
day before the blood tests were done, and not WTC air. In fact, Rottner [2002] has reported only
one mercury air sample above detection limits to date in the WTC area.
In addition, data from a U.S. Geological Survey leachability study [USGS, 2001] performed on
both indoor and outdoor WTC dust samples found mercury in leachate samples only at trace
levels (up to 18 parts per trillion [ppt] for outdoor dust and 130 ppt in indoor dust) Because only
trace levels of mercury appear to be present m indoor dust samples, the probability that harmful
levels could ever be released to the air is very low. Therefore, mercury will not be monitored in
any further indoor environment testing
Particulate Matter
Particulate Matter (as fine dust and smoke) in the 10 micron and smaller size range is inhalable
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and may cause throat and lung irritation Because of the energy released by the WTC disaster,
dust containing particulate matter in this size range was generated. If this dust had not been able
to settle, or if there had remained a continuous source of particulates being released into the
ambient air, then there would have been a concern that hazardous dust could infiltrate nearby
homes and offices. However, ambient monitoring for fine particulate matter in the WTC area has
shown that, since late October, the levels of PM 10 (inhalable dust fraction 10 microns and
smaller) and PM 2.5 (respirable fraction 2.5 microns and smaller) have been below the levels of
concern:
PM10 150ug/m3 NAAQS 24-hour average
PM2.5 65 ug/m3 NAAQS 24-hour average
40 ug/m3 Air Quality Index, 24-hour average
(moderate impact)
This indicates that there is no continuing concern of hazardous fine particulate matter entering
homes and offices in the WTC area. Therefore, particulate matter will not be monitored in any
further indoor environment testing.
Refractory Ceramic Fibers fRCH
Ceramic fibers are reasonably anticipated to be human carcinogens based on sufficient evidence
of carcinogenicity in experimental animals [IARC V.43, 1988]. When administered by
inhalation, rats of both sexes showed a significant increase in the incidence of benign and
malignant tumors of the lung However, there are no data available to evaluate the
carcinogenicity of ceramic fibers in humans [IARC V 43, 1988]
It is not expected that ceramic fiber-containing materials were present in large quantities in the
WTC buildings, since those materials are used mainly in industrial high temperature
applications.
Some air sampling has been performed for ceramic fibers in a recently completed study by
ATSDR and NYCDOH [NYCDOH, 2002]. Dunng the period from November 4 through
December 11, 2001, environmental samples were collected in 30 buildings in lower Manhattan
and four locations above 59th Street. Settled dust samples were taken both indoors and out, and
analyzed for asbestos and other fibers by PLM. Although fibrous glass was reported in many
settled dust samples, RCF was not reported as a fiber present by PLM. Air samples, also taken in
these areas, were analyzed for fibers by PCM. Six of these study area air samples appeared to
contain fiber levels in air higher than the levels found above 59th Street. Four of the samples
from areas containing fibrous glass in settled dust were re-analyzed by SEM and were not found
to contain any ceramic fibers above the detection limit (0.00004 fee).
Even though this is a limited study, it appears to confirm limited to no use of ceramic fibers in
the WTC buildings. Therefore, ceramic fibers will not be monitored in any further indoor
environment testing
Mold
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Mold was not generated during the WTC collapse or associated fires. However, mold may be
present because of actions taken in response to the collapse Substantial quantities of water were
used to extinguish the fires and to wash buildings affected by the collapse. Some of that water
entered buildings, causing indoor mold contamination. Additionally, the loss of electric power
after the collapse affected the ability of buildings' ventilation and plumbing systems to control
indoor environments. This may have contributed to indoor mold contamination in some
buildings.
The most common symptoms of exposure to mold are runny nose, eye irritation, cough,
congestion, and aggravation of asthma. Although there is evidence documenting severe health
effects of mold in humans, most of this evidence is derived from eating mold-contaminated
foods, or occupational exposures in agricultural settings, where inhalation exposures were very
high. There are no numeric standards to define "safe" levels of mold. In addition, it is very
unlikely that the existence of mold in buildings around the WTC site can be distinguished from
mold conditions existing prior to the attack. Therefore, the guidance established below is
qualitative in nature and targeted towards detecting the presence of mold and removing it, rather
than quantifying levels that pose health nsks
When inspecting a building, investigators should:
1. Look for evidence of visible mold or water damage throughout the apartment or office.
Pay particular attention to moldy odors
2 Ask the building management if water damage was noted as a result of the WTC attack or
events thereafter The investigator should be alert for situations where the loss of power
to a building may have created a situation where either the ventilation or plumbing
systems failed or leaked, creating water damage.
3 If mold contamination is encountered, it should be removed in accordance with New
York City Department of Health mold removal guidelines:
http://www.nyc gov/health/html/doh/html/epi/moldrptl html
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APPENDIX B
World Trade Center Health Effects Screening Criteria for Ambient Air
Introduction
Extensive air quality monitoring data have been collected at and around the World Trade Center
(WTC) site since 9/11/01. Table 1 (Screening Criteria) is intended to provide health protective
screening values for data evaluation Analysis has been performed on an extensive list of
potentially WTC-related contaminants. Many of the chemicals screened have demonstrated a
consistently low (i.e., below detection limits or trace amounts) trend. Consequently, the list of
contaminants in Table 1 represents those chemicals that, because of their intrinsic toxicity and
frequency/magnitude-of -detection, pose the greatest potential hazard from exposure. This
selection process (i.e., a toxicity/concentration analysis), although qualitative, reflects the
contaminant-of-concern identification process recommended in the Risk Assessment Guidance
for Superfund. Table 1 may be expanded as additional data analysis becomes available. Two
populations have been identified for assessment response/demolition (i.e., WTC site) workers;
and residents living in Lower Manhattan (e.g., Battery Park City, Tnbeca and other residential
locations close to Ground Zero). Included in the resident category are all other workers located in
Lower Manhattan with the exception of WTC site workers.
Relevant Standards
The following paradigm has been employed to develop screening values. For each of the two
identified receptor populations (i.e., site workers and residents), existing standards are utilized
where appropriate Occupational standards (i.e., OSHA PELs) are used for all site workers
conducting response/demolition activities covered by OSHA. Monitoring data from demolition
areas are compared to OSHA PELs. (For example, the OSHA PEL of 1 ppm for benzene is used
to evaluate benzene air samples taken directly from within the plume on the debris pile.)
Environmental standards (e g., NAAQS, AHERA) are utilized to evaluate monitoring data from
the site perimeter and beyond where residents or non-WTC site workers may be exposed. (For
example, lead air monitoring data from perimeter stations outside of the immediate work zone
are evaluated against the NAAQS of 1.5 ug/m3.)
Risk-Based Screening Criteria
In cases where appropriate standards do not exist, risk-based screening criteria have been
developed for residential (including the non-WTC site workers) receptors. (In the absence of
OSHA standards, it is beyond the scope of EPA's mission to develop "occupational" screening
values.) The risk assessment paradigm detailed in EPA's "Hazard Evaluation Handbook: A
Guide to Removal Actions" (HEH) was employed for this initiative (except where otherwise
noted in the Table 1 footnotes). Screening levels reflect the most current toxicity criteria (Slope
Factors and RfCs) on EPA's IRIS database.
For carcinogenic compounds excess lifetime cancer risk was set at E-04 (one-in-ten thousand).
The residential exposure scenario in the HEH was modified for carcinogens from the default of
30 years (upper-bound estimate for residency in one dwelling) to 1 year (to reflect an upper
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bound estimate for the length of time a resident may be potentially exposed to WTC-related
contaminants). In cases where the screening value based on a noncancer endpoint is more
stringent, screening values for both cancer and noncancer endpoints are presented. It is also
noted that the default 30 year exposure duration (and the 1 year site-specific adjustment) reflects
an apportionment between child (20% of total exposure duration) and adult (80 % of total
exposure duration) receptors. Because children have comparatively greater (as a function of
body weight) respiration rates than adults, the screening values presented in Table 1 are
marginally more stringent than values that would otherwise be derived by direct application of
IRIS verified Unit Risk values.
For noncarcinogenic compounds, the Hazard Quotient (chrome daily intake/RfC) was set at 10.
A Hazard Quotient of 10 is employed in the HEH to account for the fact that chronic toxicity
criteria (RfDs/RfCs) are being applied to sub-chronic exposure scenarios that are not expected to
exceed 6 months - 1 year in duration. Accordingly, a Hazard Quotient of 10 was utilized for
non-carcinogens in Table 1 to reflect a similar (i.e., upper bound of 1 year) exposure duration
It is noted that contaminants (both non-carcinogens and carcinogens, alike) can exhibit acute
effects from short-term, high-dose exposures. Because the screening values in Table 1 are based
on subchronic exposure (i.e., 1 year), acute effects from exposures that are below the screening
levels would be unlikely. Additionally, a review of California EPA's (CAL-EPA) Acute Risk
Levels demonstrates that the screening criteria in Table 1 are categorically more stringent than
the Cal-EPA's analogous acute levels.
NOTE: Individual sampling results that exceed screening values should not be interpreted to
represent the occurrence of an adverse health effect. Rather, such information indicates the need
for careful monitoring and the assessment of longer-term data trends for evaluation against
appropriate health criteria. That is, most of the screening levels have been developed to account
for continuous one year average exposure durations. Because these screening levels assume
continuous exposure for an extended duration, the average of the measured concentrations is
more appropriate for evaluating risk than an individual measurement. Consequently,
miscellaneous individual values above the screening level may not necessarily be indicative of
potential for concern
Table 1
World Trade Center Screening Criteria
Contaminant
Site Worker(l)
Resident<2)
Inorganics
Asbestos(3)
.1 ffee (PCM)
70 S/mm2 (TEM)
Cadmium
5 ug/m3
.2 ug/m3 (9)
3 ug/m3 (5)
Chromium (4)
100 ug/m3
.6 ug/m3 (5)
Lead
50 ug/m3
1.5 ug/m3 (7)
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Contaminant
Site Worker(1)
Resident(2)
Manganese
5 mg/m3
.5 ug/3 (
Semivolatiles
Dioxin/Furans (TEQ)
NA
.162 ng/m3 (5)
PCBs
1,000 ug/m3
.73 ug/m3 (6)
9 ug/m3 (5)
PAHs (16)
NA
6 ug/m3 (5'17)
Volatiles
Acetone
1,000 ppm
1 5 ppm <6)
Benzaldehyde
NA
860 ppm
Benzene
1 ppm
.02 ppm (9)
.21 ppm (5)
Benzonitnle
NA
NA
1,3 Butadiene
1 ppm
.01 ppm (5J5)
Chloromethane
100 ppm
.4 ppm (6)
2.6 ppm(5)
1,4 Dioxane
100 ppm
.5 ppm(5)
Ethanol
1,000 ppm
45 ppm (10)
Ethylbenzene
100 ppm
2.5 ppm(6)
Freon 22
1,000 ppm(14)
140 ppm
Propylene
LEL(,3)
simple asphyxiant
Styrene
100 ppm
2.3 ppm (6)
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Contaminant
Site Worker(,)
Resident(2)
alpha methylstyrene
100 ppm
1 ppm(6)
Tetrahydrofiiran
200 ppm
.9 ppm(5>
Toluene
200 ppm
1.1 ppm (6)
Xylenes
100 ppm
i ™ en
1 ppm
Reactive Gases
Acetaldehyde
200 ppm
.05 ppm C6)
1.3 ppm(5)
Formaldehyde
.75 ppm
.04 ppm <12)
.35 ppm<5)
Acrolein
.1 ppm
.0001 ppm (6)
Units
f/cc = fibers (>5 um length) per cubic centimeter of air
S/mm2 = structures (>.5 um length) per square millimeter of filter paper
ppm = parts per million in air
ug/m3 = micrograms of contaminant per cubic meter of air
ng/m3 = nanograms of contaminant per cubic meter of air
NA - Not Applicable
Footnotes:
1. "Site Workers" refers to all workers involved in the response/demolition of the World Trade
Center. Listed values are Occupational Safety and Health Administration (OSHA) Permissible
Exposure Limits (PELs), Time Weighted Averages (TWA) unless otherwise noted.
2. "Residents" refers to people living in the vicinity of the World Trade Center as well as all
other potentially exposed workers not involved in the response/demolition
3. Resident screening value is based on Asbestos Hazard Emergency Response Act (AHERA)
methodology which uses transmission electron microscopy (TEM), and because of its basis in
"background" (vs a risk basis) includes all asbestos fibers greater than 0.5 microns in length.
Worker values are based on phase contrast microscopy (PCM, - which doesn't distinguish
asbestos from other fibers) or, for results above the PCM screening value, TEM to derive a PCM
equivalence that includes all asbestos fibers greater than 5 microns in length.
4. Screening values for chromium were based on the most toxic form (hexavalent)
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5. EPA - Hazard Evaluation Handbook (HEH) (carcinogen) > 1 year of continuous exposure
equating to an excess lifetime cancer risk of one-in ten thousand
6. EPA - HEH (noncarcinogen) > Hazard Quotient (HQ) = 10
7. National Ambient Air Quality Standard (NAAQS)
- Lead is a 3 month average
- PM2 5 is a 24 hour average
- Sulfur Dioxide is a 24 hour average primary standard
8. Air Quality Index (AQI)
9 Non cancer effects based on CAL-EPA toxicity studies
10. American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit
Value (TLV)
11. Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation minimum risk level
(MRL)x 10
12. ATSDR acute MRL
13. Lower Explosive Limit (2-11 %)
14. National Institute of Occupational Safety and Health (NIOSH)
15 Proposed Reference Concentration (RfC) - HEH (noncancer) > Hazard Quotient (HQ) = 10
16. Based on Benzo(a)pyrene toxicity equivalency factor toxicity equivalency factor (TEF)
17. EPA National Center for Environmental Assessment (NCEA) provisional inhalation Slope
Factor (3.1 E 00 mg/kg/day"1)
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APPENDIX C
Basis for Tier III screening level of 1 E-04
Defensible analytical methodology and sampling protocols are being chosen for future indoor
sampling and analysis activities. The methods chosen are ones that have been published by
reputable agencies and are in common practice among testing laboratories. In some cases, minor
modifications may be made to the sampling and analytical protocols, but these will be
modifications that are well established in the laboratory community.
All protocols chosen are designed to reach the lowest level of detection that is reasonable for the
established methods. For Dioxin, Asbestos and PAHs, the sampling and analytical protocols are
designed to reach detection limits that represent risk estimate levels of 1 E-04. To reach risk
estimates of 1E-06, extraordinary modifications would have to be employed. These
modifications would either have to be incorporated into the analytical protocols to increase the
sensitivity of the required instrumentation, incorporated into the sampling protocols to achieve a
larger sample, or a combination of both. For the Chemical of Potential Concern (COPC) list, the
analytical protocols chosen are already incorporating the maximum sensitivity of the
instrumentation. Therefore, the only legitimate mechanism to lower the overall limits of
detection is to modify the sampling protocol. The two means of achieving this goal are to either
run the sampling equipment (pumps) at a higher flow rate, or for longer periods of time. For the
COPC list modifying flow rates would involve operating the equipment to achieve flow rates on
the order of 500 to 1000 liters per minute. The only equipment available to operate at such flow
rates are large units that can not be brought inside a residence. Rates this high also present
problems with creating excessive negative pressure for indoor environments, plus flow rates this
high have not been tested using the sampling protocols, and there is high likelihood of having
analyte breakthrough on the collection filters. Therefore, this is not practical. The other option
is to run the equipment for long periods of time. Again with the list of Chemicals of Potential
Concern, sampling periods of up to 800 hours (33 days of continuous operation) would be
needed to reach the E-06 risk detection levels
For silica, the analytical and sampling protocols chosen will give detection levels in the
neighborhood of 5 ug/m3. Instrumental sensitivity can not be set any higher to reach lower
detectjon levels. Also, the sampling protocols involved for this analysis have been thoroughly
validated by NIOSH. Any change m pump flow rate or sampling duration beyond what is
documented in the method will produce results that have not been validated. Therefore, the
sampling protocol should not be changed from that which is documented.
For fibrous glass the methodology is such that detection levels as low as 0.00001 f7cc can be
achieved This is well below required levels of detection for future indoor studies.
Another consideration in setting the target risk level involved the anticipated background level of
contaminants such as asbestos, dioxin and PAHs in urban indoor environments As previously
mentioned, EPA is currently conducting a study to characterize background conditions for WTC
COPCs in New York City residential dwellings. In advance of this study, a literature review was
conducted to provide a general estimate of background concentrations for carcinogenic COPCs
in urban indoor environments. It should be noted that the literature is limited in this regard For
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asbestos, ATSDR reports that "measured indoor air values range widely, depending on the
amount, type, and condition (friability) of asbestos-containing materials used in the building"
[ATSDR, 1995], In its review ATSDR notes that the studies suffer from lack of common
measurement reporting units Study results have been reported as ng/m3, f7cc (TEM) and f/cc
(PCM). Using unit conversion factors recommended by the National Research Council m 1984,
ATSDR [1995] reports that the arithmetic mean concentrations of monitoring data from a
variety of indoor locations ranged from .00003 - .006 f/cc (PCM). The proposed clearance level
for WTC-impacted residential dwellings (.0009 PCM equivalents) is within this background
range.
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APPENDIX D
Assessing Exposures to Indoor Air and to Residues on Indoor Surfaces
Introduction
The purpose of this Appendix is to provide further details on how procedures were selected to
estimate exposure to indoor air and to residues on indoor surfaces in residences impacted by the
WTC attack.
Indoor Air
Deriving clearance criteria for air samples was completed by using methods described in EPA's
"Risk Assessment Guidance for Superfund" [RAGS, 1989], These methods were developed to
assess the risk from contaminants at Superfund sites. The clearance criteria were calculated
using the formula below:
ED = Exposure Duration
Target Risk
The target risk identified for these calculations was 1 x 10-4 Appendix C explains the rationale
for this value.
Averaging Time - Carcinogens
For non-carcinogens, AT is the exposure duration expressed in days. For carcinogens, exposure
is averaged over a 70-year lifetime (the factor on which the cancer slope factors are based), and
the AT is 70 years, in days (25,550).
Exposure Duration
A value of 30 years is assumed to match upper bound estimate of time in a residence (EPA,
1997b).
Exposure Frequency
A value of 365 days/year is used to represent a full time resident
Inhalation Unit Risk
The upper-bound excess lifetime cancer risk estimated to result from continuous exposure to an
agent at a concentration of 1 ng/m3 in air The interpretation of unit risk would be as follows if
unit risk = 1.5 x 10"6 fig/m3, 1 5 excess tumors are expected to develop per 1,000,000 people if
exposed daily for a lifetime to 1 |ig of the chemical in 1 cubic meter of air. The inhalation unit
risk values used in the calculations are 2.3 E-01 for asbestos (IRIS, 2002), 2 86 E +05 for dioxin
(Dioxin Reassessment, EPA, 2001), and 7 3 E+0 for PAHs (IRIS, 2002).
Clearance criteria = (TR x AT) / (EDx EFx IUR)
where
TR = Target Risk
AT = Averaging Time - Carcinogens
EF = Exposure Frequency
IUR = Inhalation Unit Risk
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Residues on Indoor Surfaces
The most formal EPA guidance which addresses this issue is the "Standard Operating Procedures
(SOPs) for Residential Exposure Assessment" originally published by the Office of Pesticides in
1997 and updated in 2001 (EPA, 1997a and EPA, 2001a). This guidance was designed for
estimating exposures to pesticides. Pesticides are typically applied to indoor surfaces as liquid or
sprayed formulations which would create surface residues which are likely to be somewhat
different than the fine dust particles associated with the WTC attack. So while this guidance was
considered, a number of other sources were also reviewed including the Superfund guidance on
dermal contact (EPA, 1989), the procedures used to develop re-entry guidelines for the
Binghamton State Office Building (Kim and Hawley, 1985), procedures used by NJDEP for
setting interior building surface clean-up goals (NJDEP, 1993), the building clean-up procedures
presented by Michaud et al (1994) and an approach developed by the EPA Region III Superfund
program that has been employed by the U.S. Army Corps of Engineers to develop nsk-based
clean-up goals for interior surfaces at the Claremont Polychemical Superfund site in Region II
(Radian, 1999). Elements from these various methods were combined to derive the procedure
shown below. The procedures involves 3 steps: 1) estimating the amount of chemical deposited
on the skin using skin area, contact frequency and transfer efficiencies, 2) estimating the dermal
dose based on an absorption fraction and 3) estimating the ingestion dose based on the fraction of
material on hands that is transferred to the mouth.
1. Estimating Amount of Chemical Deposited on Skin
Ds = C x SA x CF x FTSS x EF x ED
Ds =
Amount of chemical deposited on skin (mg)
C
Concentration of chemical on contaminated surface (mg/cm2)
SA =
Exposed skin surface area (cm2)
CF =
Contact frequency of skin against surface (1/day)
FTSS =
Fraction transferred from surface to skin
EF =
Exposure frequency (days/year)
ED =
Exposure duration (years)
2. Estimating Dermal Dose
Dd = (Ds x (1 - FTSM) x ABSd) / (BW x AT)
Dd = Dermal dose (mg/kg/day) BW = Body weight (kilograms)
FTSM = Fraction transferred from skin to mouth AT = Averaging time (days)
ABSd = Dermal absorption fraction
3. Estimating Oral Dose
Do = (Ds x FTSM x ABSo) / (BW x AT)
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Do = Oral dose (mg/kg/day) BW = Body weight (kilograms)
FTSM = Fraction transferred from skin to mouth AT = Averaging time (days)
ABSo = Oral absorption fraction
The surface concentration term (C) was assumed to remain constant over the entire 30 year
exposure period. This is probably not true for surfaces in the residences impacted by the WTC
attack. Surface loadings will decline as a result of volatilization, chemical degradation, surface
cleaning and transfers to skin/clothing. While some redeposition will also occur, the net long
term effect should be a gradual decline. In this sense, the method will overestimate exposures.
This same issue has been recognized in similar assessments involving building clean-ups and
pesticide exposures:
• Two scenarios were considered in developing the procedures used to develop re-entry
guidelines for the Bingbamton State Office Building (Kim and Hawley, ] 985). One
assumed a constant surface concentration and the other assumed a first order exponential
decay
The OPP guidance (EPA, 1997a and EPA, 2001a) uses a "dissipation" factor to account for
degradation and other loss mechanisms after pesticide application. Similarly, Durkin et al
(1995) has proposed a time-dependent transfer coefficient method for lawn treatment
pesticides.
• Michaud et al (1994) proposed a mass balance model which accounts for losses from
surfaces associated with building clean-ups.
Thus, while methods have been proposed to deal with changes in surface residue strength over
time, it is uncertain how well these apply to the situation in residences near WTC. Thus for
purposes of this screening assessment, it was decided to assume constant levels.
4. Calculating Clearance Criteria
In order to calculate a clearance criteria for wipe samples, the formulas identified above need to
be rearranged to derive a concentration based on the target cancer risk or non-cancer hazard. The
clearance criteria for settled dust, using a wipe sample, for each COPC can be calculated using
the formula listed below and the exposure parameters listed in Table 3 in the body of the
document.
Clearance criteria (mg/m2) = (TR x BWx AT) /[((Ddx CSFd) + (Do x CSFo)) x EFx ED]
The other terms in this procedure and associated uncertainties are discussed below:
Exposed Skin Surface Area (SAI
The skin surface area of 400 cm2 is a typical value for the palm side of adult hands (EPA, 1997b)
which is the body part that is most likely to contact surfaces.
Contact Frequency fCFl
Michaud et al (1994) assumed 8 contacts per day, apparently based on professional judgment.
Low-end values of 1/day and "worst-case" rates of 24/day (3/hour) may be assumed as a matter
3
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of professional judgment; such exposure would obviously involve a very physical job with
frequent contact with the walls and floor. The value recommended here is 16 contacts per day
and is based on professional judgement. If available, site-specific activity data should take
precedence.
Fraction Transferred from Surface to Skin fFTSS'l
This will vary depending on type of surface, type of residual, hand condition, force of contact,
etc Rodes et al 2001 conducted experiments on particle transfer to dry skin and measured
transfers of 10% from carpets and 50% from hard surfaces. These transfer efficiencies were
found to decline with repeated contacts. The OPP guidance recommends 5% of application rate
for carpets and 10 % for hard surfaces (EPA, 1997a). USEPA has previously assumed transfer of
0.5 for PCBs (EPA, 1987) based on an Office of Toxic Substances (OTS) assessment. Michaud
et al (1994) assumed 0.5 for PCBs and dioxins, but stated that 0.1 might be more realistic. In
developing re-entry guidelines for the Binghamton State Office Building after a fire, a 100%
transfer was assumed (Kim and Hawley, 1985). In a study of Malathion uptake from different
surfaces, USEPA-EMSL found that FTSS of malathion from painted sheetrock to human hands
was only 0.0003. (Mean transfer from vinyl flooring to hands was 0.0018, and from carpet to
hands was 0.0152.) Malathion is a pesticide assumed to have hpophihcity more similar to PCBs
than to volatiles or metals. However, the representativeness of such a number for PCBs and
dioxins is unknown. PCBs are more lipophilic (have higher Kows) than malathion. A value of
5% is recommended here. Although this is on the low end of the literature values, when
combined with the high contact frequency, it provides a fairly high total transfer to skin.
Exposure Frequency CEF1
A value of 365 days/year is used to represent a full time resident.
Exposure Duration (EDI
A value of 30 years is assumed to match upper bound estimate of time in a residence (EPA,
1997b)
Fraction Transferred from Skin to Mouth (FTSM1
Michaud et al (1994) assumed that all of the residues deposited on the fingertips would be
transferred to the mouth, twice per day. A similar approach is used in the OPP guidelines. In the
Binghamton re-entry guideline denvation, a range of factors were used. 0.05, 0 1, and 0.25
representing the fraction of residue on hand that is transferred to the mouth (Kim and Hawley,
1985). A similar value of 10% is recommended here.
Oral Absorption Fraction CAB SO)
For chemicals whose dose-response parameters are based on experiments in which the absorption
fraction is similar to the one expected in the exposure scenario, there is no need to adjust the RfD
or CSF.
Body Weight (BW")
A value of 70 kilograms is assumed which represents an average adult (EPA, 1997b).
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Averaging Time (AT)
For non-carcinogens, AT is the exposure duration expressed in days. For carcinogens, exposure
is averaged over a 70-year lifetime (the factor on which the cancer slope factors are based), and
the AT is 70 years, in days (25,550).
Dermal Absorption Fraction (ABSdl
This parameter is chemical-specific. Dermal absorption fractions of 0 06 for PCBs and 0.03 for
dioxins from soil were first proposed in USEPA, 1992 and more recently adopted in EPA 2001b.
Michaud et al (1994) used 0.02 for dioxins and 0.03 for PCBs uptake from a sooty surface, based
on the ranges of estimated ABSd values for soil. The Binghamton panel used a range of values
for PCBs (0.01, 0.1, and 0.5) and dioxins (0.01 and 0.1) (Kim and Hawley, 1985).
Reported ranges for dermal uptake for PCBs in solvent vehicles are reported to range from 15 to
56%, with most of the values clustering around 20% (ATSDR, 1993). Reported ranges for
2,3,7,8-TCDD in solvent vehicles are reported to range from 1 to 40% (ATSDR, 1988).
Therefore, it seems that even if absorption from the wall material might be enhanced by residual
solvent, the maximum possible absorption of 100% would be unrealistic even for worst-case
exposure.
The values recommended here of 3% for dioxins and 13% for PAHs are based on EPA, 2001b.
Toxicity Values
There are two toxicity values that can be used to calculate screening values, a Reference Dose
(RfD) for non-carcinogenic compounds and a Cancer Slope Factor (CSF) for carcinogenic
compounds. The RfD is defined as an estimate (with uncertainty spanning perhaps an order of
magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that
is likely to be without an appreciable risk of deleterious effects dunng a lifetime. It can be
denved from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied
to reflect limitations of the data used. The CSF is defined as an upper bound, approximating a
95% confidence limit, on the increased cancer risk from a lifetime exposure to an agent. This
estimate, usually expressed in units of proportion (of a population) affected per mg/kg/day, is
generally reserved for use in the low-dose region of the dose-response relationship, that is, for
exposures corresponding to risks less than 1 in 100 As the cancer endpoint was more sensitive,
CSFs were used instead of RfDs. The CSFs used to calculate the clearance criteria are: 1.0 E+6
for dioxin (Dioxin Reassessment, EPA, 2001) and 7.3 E+0 for PAHs (IRIS, 2002).
5
-------
References
Agency for Toxic Substances and Disease Registry (ATSDR). 1988. Toxicological Profile for
2,3,7,8-Tetrachlorodibenzo-p-dioxin. United States Public Health Service, ATSDR, Atlanta,
GA.
ATSDR 1993. Toxicological Profile Update for Polychlorinated Biphenyls. United States
Public Health Service, ATSDR, Atlanta, GA.
Durkin, P.R., L. Rubin, J. Withey, and W. Meylan. 1995. Methods of assessing dermal
absorption with emphasis on uptake from contaminated vegetation. Toxicology and Industrial
Health ll(l):63-79.
Kim N K and J. Hawley. 1985. Re-Entry Guidelines: Bingharnton State Office Building. New
York State Dept. of Health, Bureau of Toxic Substances Assessment, Division of Health Risk
Control. Albany, NY. August. Document 0549P.
EPA. 1987. Polychlorinated Biphenyls: Spill Cleanup Policy. Final Rule. Federal Register,
Volume 52, Number 63. April 2.
EPA. 1989. Risk Assessment Guidance for Superfimd Volume T Human Health Evaluation
Manual {Part A). Interim Final. Office of Emergency and Remedial Response, Washington,
D,C. December.
EPA. 1992. Dermal Exposure Assessment: Principles and Applications. Interim Report. Office
of Health and Environmental Assessment, Washington, D.C. January EPA/600/891/011/B
EPA, 1997a. Draft Standard Operating Procedures (SOPs) for Residential Exposure Assessment
Office of Pesticides Programs. December 19,1997.
EPA, 1997b. Exposure Factors Handbook. EPA/600/P95/002
EPA, 2001a. Science Advisory Council for Exposure. Policy Number 12 on Recommended
Revisions to the Standard Operating Procedures (SOPs) for Residential Exposure Assessments
Revised: February 22, 2001
EPA, 2001b. Risk Assessment Guidance for Superfund Volume 1. Human Health Evaluation
Manual (Part E, Supplemental Guidance for Dermal Risk Assessment) Interim.
EPA/540/R/99/005. Review Draft
Michaud, J M , S.L Huntley, R A. Sherer, M.N. Gray, and D.J. Paustenbach 1994. PCB and
dioxin re-entry criteria for building surfaces and air. Journal of Exposure Analysis and
Environmental Epidemiology 4(2):197-227.
New Jersey Department of Environmental Protection (NJDEP) 1993. Technical Basis and
6
-------
Background for Cleanup Standards for Contaminated Sites. N.J.A.C. 7:26D (Draft).
Radian International. 1999. Development of risk-based wipe sample cleanup levels at the
Claremont Polychemical Superfund site in Old Bethpage, New York. Prepared for: U.S. Army
Corps of Engineers.
Rodes, C., R. Newsome, R Vanderpool, J Antley, R Lewis. 2001. Experimental methodologies
and preliminary transfer factor data for estimation of dermal exposure to particles Journal of
Exposure Analysis and Environmental Epidemiology, 11.123-139.
7
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APPENDIX E
IEUBK Model Results for Lead in Air
LEAD MODEL FOR WINDOWS Version 1.0 Build 251
Model Version: 1.0 Build 251
User Name:
Date:
Site Name:
Operable Unit'
Run Mode: Research
The time step used in this model run: 1 - Every 4 Hours (6 times a day).
****** ******
Indoor Air Pb Concentration. 100.000 percent of outdoor.
Other Air Parameters:
Age
Time
Ventilation
Lung
Outdoor A

Outdoors
Rate
Absorption
Pb Cone

(hours)
(mA3/day)
(%)
(ug Pb/mA3)
.5-1
0.000
2.000
32.000
1 000
1-2
0.000
3.000
32.000
1.000
2-3
0.000
5.000
32.000
1.000
3-4
0 000
5.000
32.000
1 000
4-5
0.000
5.000
32.000
1 000
5-6
0.000
7 000
32 000
1.000
6-7
0.000
7.000
32.000
1 000
****** Qjgt ******
Age Diet Intake(ug/day)
.5-1
5.530
1-2
5.780
2-3
6.490
3-4
6.240
4-5
6.010
5-6
6.340
6-7
7.000
1
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****** Drinking Water ******
Water Consumption:
Age Water (L/day)
.5-1 0.200
1-2 0.500
2-3 0 520
3-4 0.530
4-5 0.550
5-6 0 580
6-7 0 590
Drinking Water Concentration: 4.000 ug Pb/L
****** Soil & Dust ******
Multiple Source Analysis Used
Average multiple source concentration: 240.000 ug'g
Mass traction of outdoor soil to indoor dust conversion facto:. 0.700
Ouldoor airborne lead to indoarbausehold dust lead concentration: 1Q0 000
Use alternate indoor dust Pb sources? No
Age Soil (ug Pb/g) House Dust (ug Pb/g)
.5-1 200.000 240.000
1-2 200.000 240.000
2-3 200.000 240.000
3-4 200.000 240.000
4-5 200.000 240.000
5-6 200.000 240 000
6-7 200 000 240.000
****** AJtemate Intake ******
Age Alternate (ug Pb/day)
.5-1
0.000
1-2
0.000
2-3
0.000
3-4
0 000
4-5
0 000
5-6
0.000
6-7
0.000
?
-------
****** Materna] Contribution" Infant Model ******
Maternal Blood Concentration: 2.500 ug Pb/dL
*****************************************
CALCULATED BLOOD LEAD AND LEAD UPTAKES'
*****************************************
Year
Air
Diet
Alternate
Water

(ug/dL)
(ug/day)
(ug/day)
(ug/day)
5-1
0640
2.521
0.000
0 365
1-2
0.960
2 608
0.000
0.902
2-3
1.600
2.963
0.000
0.950
3-4
1.600
2.886
0.000
0.981
4-5
1.600
2.842
0.000
1 040
5-6
2.240
3 022
0.000
1.106
6-7
2.240
3.349
0.000
1.129
Year
Soil+Dust
Total
Blood

{ug/day)
(ug/day)
(ug/dL)

.5-1
5 162
8 688
4.7

1-2
8.113
12.583
5.2

2-3
8.210
13.723
50

3-4
8318
13.785
4.8

4-5
6.298
11.780
4 I

5-6
5.714
12.081
3.7

6-7
5.417
12.135
3.5

-------
IEUBKwin3Z Model 1.0 build 251 - [Distribution Probability Percent]
| 3 FtJe Output View Help
ES1&

j£|xj
100
<]_
Cutoff = 10.000 ug/dl
Geo Mean = 4 410
GSD = 1.600
% Above = 4 076
J
15 10 21
Blood Pb Cone (ug/dL)
24
27
30
33
36
Age Range = 0 to 04 months
Time Step = Every 4 Hours
Run Mode = Research
J
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-------

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ATTACHMENT B
DATA VALIDATION
STANDARD OPERATING PROCEDURES
The following SOPs were used by the Quality Assurance Technical Support Contractor for the
validation of analytical data:
SOP QATS-70-077-01 THE DATA VALIDATION OF TRANSMISSION ELECTRON
MICROSCOPY (TEM) DATA PACKAGES GENERATED
USING ASTM METHOD 5755-95 (Dec. 17, 2002)
SOP QATS-70-078-01 THE DATA VALIDATION OF PHASE CONTRAST
MICROSCOPY (PCM) DATA PACKAGES GENERATED
USING NIOSH METHOD 7400 (Dec. 17, 2002)
SOP QATS-70-076-01 THE DATA VALIDATION OF TRANSMISSION ELECTRON
MICROSCOPY (TEM) DATA PACKAGES GENERATED
USING EPA 40 CFR, PART 763, SUBPART E (Dec. 17, 2002)
SOP QATS-70-075-01 THE DATA VALIDATION OF INORGANIC METALS DATA
PACKAGES GENERATED USING EPA METHOD 6010B AND
EPA METHOD 7471A (Dec. 17, 2002)
SOP QATS-70-074-01 THE DATA VALIDATION OF HRGC/HRMS DATA
PACKAGES GENERATED USING EPA METHOD 8290 (Dec.
17,2002)
SOP QATS-70-073-02 VALIDATING SILICA DATA GENERATED BY METHOD
MSD 0700 X-RAY DIFFRACTION (XRD) (Dec. 17, 2002)
SOP QATS-70-071 -01 THE DATA VALIDATION OF TRANSMISSION ELECTRON
MICROSCOPY (TEM) DATA PACKAGES GENERATED
USING ASTM METHOD D 6480-99 (Dec. 17, 2002)
SOP QATS-70-072-01 THE DATA VALIDATION OF POLYNUCLEAR AROMATIC
HYDROCARBON (PAH) WIPE SAMPLE DATA PACKAGES
GENERATED USING EPA METHOD 8270C (MODIFIED)
(Dec. 17, 2002)
SOP QATS-70-070-01 THE DATA VALIDATION OF MAN-MADE VITREOUS
FEBERS/MMVF) DATA PACKAGES BY POLARIZED LIGHT
MICROSCOPY (PLM) AND SCANNING ELECTRON
MICROSCOPY (SEM) GENERATED USING MSD 0310
-------
E
-------
ATTACHMENT C
EMSL ANALYSIS
STANDARD OPERATING PROCEDURES
The following SOPs were used by the contracted laboratory, EMSL for the analysis of Man-
Made Vitreous Fibers (MMVF) and Silica:
EMSL MSD 0310 OPERATING PROCEDURE FOR THE ANALYSIS OF MAN-
MADE VITREOUS FIBERS FOR THE EPA RESIDENTIAL
SAMPLING PROJECT (Feb 2002, Modified Mar 2002)
EMSL MSD 0700 OPERATING PROCEDURE FOR THE ANALYSIS OF SILICA
(a-quartz, cnstobalite or tndymite) BY X-RAY DIFFRACTION
FOR THE EPA RESIDENTIAL SAMPLING PROJECT
-------
[i
-------
ATTACHMENT D
SAMPLING AND ANALYTICAL METHODS
1. NIOSH Method 7400: Asbestos and Other Fibers by PCM; NIOSH Manual of Analytical
Methods; U.S. Department of Health and Human Services, National Institute of
Occupational Safety and Health: Washington, DC, 1994.
2 AHERA Asbestos-Containing Materials in Schools. Code of Federal Regulations, Part
763, Title 40, 2001.
3 EMSL MSD 0300: Material Science Division Operating Procedures for Man-Made
Vitreous Fiber ID; EMSL Analytical, Inc., NY, 2001.
4. NIOSH Method 7300: Elements by 1CP, NIOSH Manual of Analytical Methods; U.S.
Department of Health and Human Services, National Institute of Occupational Safety and
Health. Washington, DC, 1994.
5 EPA SW-846 6010B: Inductively Coupled Plasma-Atomic Emission Spectrometry, Test
Methods for Evaluating Solid Wastes Physical/Chemical Methods; U.S. Environmental
Protection Agency, Office of Solid Waste: Washington, DC, 1996.
6 NIOSH Method 7500. Silica, Crystalline, by XRD, NIOSH Manual of Analytical
Methods, U.S. Department of Health and Human Services, National Institute of
Occupational Safety and Health: Washington, DC, 1998.
7. ASTM Standard D 5755-95: Standard Test Method for Microvacuum Sampling and
Indirect Analysis of Dust by Transmission Electron Microscopy for Asbestos Structure
Number Concentrations', American Society for Testing and Materials- West
Conshohocken, PA, 2001.
8. ASTM Standard E 1973-99. Standard Practice for Collection of Surface Dust by Air
Sampling Pump Vacuum Technique for Subsequent Lead Determination, American
Society for Testing and Materials: West Conshohocken, PA, 2001
9 ASTM Standard D 6480-99. Standard Test Method for Wipe Sampling of Surfaces,
Indirect Preparation, and Analysis for Asbestos Structure Number Concentration by
Transmission Electron Microscopy, American Society for Testing and Materials: West
Conshohocken, PA, 2001
10 ASTM Standard D 6661-01 Standard Practice for Field Collection of Organic
Compounds from Surfaces Using Wipe Sampling; American Society for Testing and
Materials: West Conshohocken, PA, 2001.
-------
11. EPA SW-846 8290: Poly chlorinated Dibenzodioxins (PCDDs) and Polychlorinated
Dibenzofurans (PCDFs) by High-Resolution Gas Chromatography/High-Resolution
Mass Spectrometry (HRGC/HRMS); Test Methods for Evaluating Solid Wastes
Physical/Chemical Methods; U S. Environmental Protection Agency, Office of Solid
Waste: Washington, DC, 1994
12. EPA SW-846 8270C: Semivolatile Organic Compounds by Gas Chromatography/Mass
Spectrometry (GC/MS), Test Methods for Evaluating Solid Wastes Physical/Chemical
Methods; U S. Environmental Protection Agency, Office of Solid Waste: Washington,
DC, 1996.
13. Guidelines for the Evaluation and Control of Lead-Based Paint Hazards in Housing,
U.S. Department of Housing and Urban Development Washington, DC, 1995; Appendix
13 1 Wipe Sampling for Settled Lead-Contaminated Dust.
14. NYSDOH Method 198.1: Polarized-Light Microscope Methods for Identifying and
Quantitating Asbestos in Bulk Samples; New York State Department of Health,
Environmental Laboratory Approval Program: Albany, NY, 1997
15 NYSDOH Method 198.4: Transmission Electron Microscope Methods for Identifying
and Quantitating Asbestos in Non-Friable Organically Bound Bulk Samples; New York
State Department of Health, Environmental Laboratory Approval Program. Albany, NY,
1997.
-------
1
-------
ATTACHMENT E
Photographs of Sample Collection Activities
-------
Photo 2: Common Space Air Sampling Set up and Operation with co-located
duplicate samples
-------
Photo 3: Calibration of Air Sampling Pumps
-------
Photo 4: Use of FORMS II Lite™ in the field for generation of sample labels,
chain of custody, and sample management.
Photo 5: Collection of Microvacuum Samples on fabric furniture.
-------
B"
Photo 6: Common Space Floor Wipe Template Set up

Photo 7: Residential Wall Wipe Sampling
-------
Photo 8: Counter Wipe Sampling of a Common Space
-------
-------
ATTACHMENT F
National Institute of Standards & Technology - Certificate of
Analysis, Standard Reference Material 2581
Appendix 14.3: Procedure for the Preparation of Field Spiked
Wipe Samples of the Guidelines for the Evaluation and Control
of Lead-Based Paint Hazards in Housing.
-------
Certificate 2581
http //patapsco nist gov/srmcalalog /view_cert2gif cfm',ccrtificatc=2581
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Standard Reference Materials;
SUM Home Ordering Information
Certlfieates/MSDS
Price List

National Inili
Standards and Todii
SRM Search:
^DnstxtntB nf Sc ^dtyjxnlrrg^
(derttftcate of J^nal^sts
Standard Reference Material® 2581

Powdered Paint
Nominal 0.5 %Lead
This Standard Reference Material (SRM) is intended for use m the evaluation of methods and for the calibration of
apparatus used to determine lead in paint SRM 2581 is composed of paint collected from the interior surfaces of
housing A unit consists of 35 g of powdered paint material, 99+ % of which, passes a ICQ yim (No 145) sieve The
certified mass fraction of lead, given below, is based on measurements by isotope dilution inductively coupled
plasma mass spectrometry (ID-ICPMS) with a minimum sample size of 100 mg The certified value is reported on a
dry basis (see Instructions for Drying)
Certified Mass Fraction
Lead Content 0 449% ±0 011 %
The uncertainly in the certified value is calculated as
U=kuB
where is the combined standard uncertainty' calculated according to the ISO Guide [1] and k is a coverage factor
The value of ue is intended to represent at the level of one standard deviation, the combined effect of uncertainty-
components associated with matenal inhcmogeneity and ID-ICPMS measurement uncertainty In the absence of
Type B uncertainties (which are negligible here in comparison with Type A), the expanded uncertainty (tf) given is
for a 95 % prediction interval The coverage factor, k = 2 57, is the Student's f-value for a 95 % prediction interval
with 5 degrees of freedom
NOTICE AND WARNING TO USERS
Expiration of Certification: The certification of this SRM lot is valid within the measurement uncertainties
specified until December 31, 2010, provided the SRM is handled and stored in accordance with the instructions
given in this certificate (see Use) However, the certification will be nullified if the SRM is contaminated or
modified
Stability: This matenal is considered to be stable NIST will monitor this material and will report any substantial
changes in certification to the purchaser Return ofthe attached registration card will facilitate notification
Use: To relate analytical determinations to the certified value on this Certificate of Analysis, a minimum sample
mass of 100 mg should be used and the sample should be dried according to the Instructions for Drying Sample
preparation procedures should also be designed to effect complete dissolution in order to relate the determmedvalue
to the certified value This SRM must be stored in an air conditioned environment or similar cool and dry
environment away from sunlight and fumes
The support aspects involved in the preparation, certification, and issuance of this SRM were coordinated throu^i
the Standard ReferenceMatenals Program by B S MacDonald
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3/12/03 4 25 PM
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Certificate 2581
http //patapsco nist gov/srmcatalog /view_cert2gif cfm')certif]ca1e=2581
The overall direction and coordination of the technical measurements leading to certification of this SRM were
performedbyJ R DeVoe, P A Pella, andRL Walters,Jr ofthe NIST Analytical Chemistry Division
Statistical c onsultation was provided by S D Leigh ofthe NIST Statistical Engineering Division
Partial financial support for the development of this SRM was provided by the U S Environmental Protection
Agency (EPA) under the direction of project managers SL Harper andME Beard ofthe EPA Office of Research
and Development, National Exposure Research Laboratory, ResearchTnangle Park,NC
COLLECTION,PREPARATION, AND ANALYSIS
Collection: The paint matenal for this SRM was collected pnmanly in North Carolina from vanous intenor wall
surfaces of old housing which, for the most part, were painted pnor to 1945 The matenal was collected under
the direction of the Research Triangle Institute and the U S Environmental Protection Agency Collection of
paint by dry scraping and its initial evaluation for use as SRM 2581 were performed by JD Neefus,
E E Williams, and D B Binstock, of the Research Triangle Institute, Research Triangle Park, NC, under the
leadership of WF Gutknecht
Preparation: The largest pieces ofdebns and foreigi matenal were first removedby hand Next, the matenal was
coarsely chipped in a large-capacity blender fitted with a stainless steel blade The matenal was then further ground
in small batches in a ball mill Each batch was sieved and the fraction that did not pass a 100 |im (#145) sieve was
returned for further grinding with a fresh charge of coarse paint matenal All matenal of a size less than 100 |im
was combined and blended as a single batchbefbre being bottled in 35 g units
Analysis: Certification analysis by ID-ICPMS was performed by ES Beaiy and KE Murphy of the NIST
Analytical Chemistiy Division X-ray fluorescence homogeneity analysis was performed by AF Mallow and
P A Pella and inductively coupled plasma-optical emission spectrometnc (ICP-OES) analysis was performed by
L J Wood ofthe NIST Analytical Chemistry Division
The ICP-OES analysis data given in Table 1 provide information on the concentrations of major constituents other
than lead in the matenal These values listed are not certified, but are given only to provide additional information
on the matrix
Instructions for Drying: Samples of this SRM should be dned in an air atmosphere at 105 ° C for 2 h At NIST,
loss on drying according to this procedure was about 1 % relative by mass However, under different conditions of
humidity, the mass loss could vary In order for users to directly relate their analyses to the certified value, loss on
drying corrections should be measured and applied at the tune ofthe analysis
Environmental Lead Proficiency Analytical Testing Program Resulte: This matenal was included as an
unknown in the Environmental Lead Proficiency Analytical Testing Program (ELPAT) administered by the
Amencan Industnal Hygiene Association (AIHA) Conventional dissolution methods employed by
participating laboratones include hotplate, microwave, and other techniques such as sealed bomb dissolutions
and leaching techniques Instrumental determinations were performed using inductively coupled plasma mass
spectrometry (ICPMS), inductively coupled plasma-optical emission spectrometry (ICP-OES), flame atomic
absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS) and X-ray
fluorescence spectrometry (XRF) Information from this study is provided to indicate the state of the practice
for lead in paint measurements using such methods A summary of the round robin lead results obtained from
ELPAT Reference Laboratones for SRM 2581 is presented in Table 2 The SRM 2581 is identified as round
robin 015, paint #3 in the ELPAT report
2 of 3
3/12/03 4 25 PM
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Certificate 2581 http //patapsco mst gov/srmcatalog /vtew_cert2gif cfm7cenificate=25S 1
SUPPLEMENTAL INFORMATION
Table 1 Information Values for Major Constituents of SRM 2581
Element Mass Fraction (%)
A1 2
Ca 11
Fe 0 4
Mg 1
Ti 12
Zn 2
T able 2 Environmental Lead Proficiency Analytical T esting (ELPAT) Program
Summary Statistics of Reference Laboratones for Round Robin 013*
Sample n
j Mean
Minimum
| Maximum
I
j
i
Paint 3 80
j 0 417 %
0 349 %
j 0 470 %
| 0 030
!
'These results trt provided to demorctrtt* user entrance vrahthis mUensl Thiy were not used mc»lcul«tinglhe certified vtlie of SRM
2581
S is one ftsndtni deviation
REFERENCE
[1] Guide to the Expression of Uncertainly m Measurement, ISBN 92-67-10188-9, 1st Ed, ISO, Geneva,
Switzerland, (1993) See also Taylor, B N and Kuyatt, C E, "Guidelines for Evaluating and Expressing the
Uncertainty of NIST Measurement Results," NIST Technical Note 1297, U S Government Printing Office,
Washington, D C, (1994)
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3/12/03 4 25 PM
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Appendix 14.3: Procedure for the Prepara-
tion of Field Spiked Wipe Samples
There is currently no analytical grade wipe media suitable for wipe sampling in residences. A
variety of commercial media are being used instead (see Appendix 13 1). Because laboratory
accreditation programs do not currently provide spiked wipe samples using wipe sampling media
commonly used in the field, it is necessary to prepare spiked wipe samples using the specific
brand of wet wipes that will actually be used in order to determine if the laboratory digestion
procedure is capable of achieving recovery rates between 80 - 120% for the specific brand of
diaper wipe used in the field. Some reports indicate that recovery rates can be as low as 40%
using certain types of wipes.
These field spiked samples are in addition to those the laboratory prepares for its own internal
QA/QC program. The samples are not actually prepared in the field, but are manufactured under
laboratory conditions. They are then relabelled in the field and inserted into the sample stream
in a random and blind fashion. The spikes should be prepared using the same lot as that used
in the field, since recoveries can vary by lot The lot should be analyzed before use to ensure
that there is not background contamination.
The following procedure may be used to prepare spiked wipe samples.
1 Obtain a Standard Reference Material containing a certified concentration of lead, such as
NIST Standard 1579a (Powdered Lead-Based Paint) or Standard 1648 (Urban Particulate),
or a traceable secondary standard with a known amount of lead.
2. Weigh out between 50 - 500 jig of lead (not total dust) to the nearest microgram.
3 Don a new disposable glove to handle each new wipe sample.
4 If tared weighing boats are used, quantitatively transfer all of the material from the boat
to the wipe by wiping the boat thoroughly.
5. If glassine paper is used, be certain that the dust transfer was complete.
6 Do not let the wipe touch any other surface Fold the wipe with the spiked side inward
and carefully insert it into a non-sterilized 50 ml centrifuge tube or other hard-shelled
container that is identical to the containers that will hold the field samples. The containers
holding the spiked samples should be indistinguishable from those holding the field
samples so that the analysis can be performed blindly This means the same container or
tube should be used to hold field samples and wipe samples.
7 Have the spiked sample inserted into the sample stream randomly, with at least one spiked
sample for each 50 field samples analyzed and one blank for each sample batch.
App 14.3-1
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